Question 1

As amphibians move from one area to another to breed, crossing the highway would lead to more deaths

Question 2

The diagram is meosis due to the doubled amount of chromosomes. During mitosis Anaphase and meiosis Anaphase I the same movement of chromosomes from the midline of the cell to the poles happen. The only difference is there is double the amount of DNA in chromosome form

Question 3

Chemical energy is stored within the bonds of the atoms and molecules that make up a substance. It is a type of potential energy. Once released from a substance, the substance is transformed into a new substance. So the answer is a type of potential energy

Question 4

Each branch off of the phylogenetic tree represents a species that is a common ancestor between the known species. The closer the branch off is to the species the more related it is. Therefore the related species to B is the common ancestor between A,C,D

Question 5

Darwin observed that species vary both globally and locally

Summary of Darwin's Theory of Evolution

• A species is a population of organisms that interbreeds and has fertile offspring.

• Living organisms have descended with modifications from species that lived before them.

• Natural selection explains how this evolution has happened:

— More organisms are produced than can survive because of limited resources.

— Organisms struggle for the necessities of life; there is competition for resources.

— Individuals within a population vary in their traits; some of these traits are heritable -- passed on to offspring.

— Some variants are better adapted to survive and reproduce under local conditions than others.

— Better-adapted individuals (the "fit enough") are more likely to survive and reproduce, thereby passing on copies of their genes to the next generation.

— Species whose individuals are best adapted survive; others become extinct.

Question 6

Actin Filaments.: Micro filament, usually layered between thick myosin filaments. microtubules : diameter of about 24 nm and are usually found in groups of 13 protofilaments. The basic structural subunit is a dimer of two similar proteins, and tubulin. Used to help in cell shape and movement.Keratin Filaments: a class of intermediate filaments that form a network within epithelial cells and anchor to desmosomes, thus imparting tensile strength to the tissue.Dynein: a motor protein (also called molecular motor or motor molecule) in cells which converts the chemical energy contained in ATP into the mechanical energy of movement.Phosopholipid Bilayer: hydrophobic tails, hydrophilic heads. Make yp the cell membrane

Question 7

They are derived from the apical meristems.Apical meristems are plant tissue that don’t know what they are yet and are found at the root and shoot end of plants and are ready to actively divide and mature into the different tissue types of a plant.

Question 8

The polymerase chain reaction (PCR) requires primers. produce millions of copies of a specific DNA sequence in approximately two hours. This automated process bypasses the need to use bacteria for amplifying DNA. Primers are used to allow the Taq ribosome to start sequencing DNA fragments that are being amplified. https://www.youtube.com/watch?v=HMC7c2T8fVk

Question 9

ATCGTAGCThe template strand of DNA is the opposite of the coding strand of DNA because the pairs would match. It would start at the 3’ end go to the 5’. So look at the ends and compare to see if pairs match. In RNA T would be replaced by U. AU, TA, UAhttps://www.youtube.com/watch?v=5bLEDd-PSTQ

Question 10

Phosphodiester linkage or bonds exist between the phosphate of one nucleotide and the sugar of the next. This forms the sugar phosphate backbone of DNA. This bond is formed from a condensation reaction between water and the phosphate and sugar, sometimes called a dehydration reaction.

Question 11

Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart.

As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.

When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts.

As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

The pulmonary vein empties oxygen-rich blood from the lungs into the left atrium of the heart.

As the atrium contracts, blood flows from your left atrium into your left ventricle through the open mitral valve.

When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts.

As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body

Question 12

A line--> Epinephrine causes an increase in dilation of blood vessels and heart beat causing an increase in blood pressure.

Question 13

P generation is the parent generation. F1 is their children. F2 would be the F1’S Children.

Offspring with H1 present in it’s genotype (combination of letters) is 75% because all but one square have at least one H1.Phenotype is the physical

look of the trait how it looks.

Question 14

DNA associated with histone proteins.Bacteria have no nucleus and their DNA floats freely in their cytoplasm in a plasmids or one large central chromosome. Archea also do not have a nucleus but their DNA is stored in histone proteins that allow the DNA to be wrapped but and stored around the protein. The same histone proteins are used to make the chromosome in Eukaryotic cells that are stored in the nucleus of these cellsBacteria and Archea have prokaryotic cells: no nucleus, not membrane bound organelles, very basicEukaryotic cells: animal and plant cells: have a nucleus, have membrane bound organelles, more complex

H1 H2H1 H1H1 H1H2H2 H1H2 H2H2

Question 15

Correct statement is Photosynthesis is endothermic. During photosynthesis the photons of light are used to drive the electron transport chain to create sugar and CO2. By taking in the light and driving this reaction it is using heat not releasing heat. Heat release or use is considered energy creation or use.

Question 16

Hind limb bones in whales are a shared ancestral trait from an ancestral terrestrial species in the evolutionary history. This is known as a vestigial organ. It is left over from an ancestral version of the species that used it for a specific function the current evolved form of the species not longer needs it. Other examples include our appendix and wisdom teeth.Whales were related to an ancestor species that was very similar to wolves.

Question 17

Microvilli contain a role in absorption. The microvilli increase surface area and absorption of nutrients and water into the blood stream. A microvilli contain a capillary network and a lacteal to collection nutrients from digesting food.

Question Decrease the concentration of unsaturated fatty acids in the membrane. The

18 phospholipid bilayer that makes up the cell membrane is made up of lipids which are unsaturated fats. These fats are hydrophobid and repeal water forming astrong barrier around the cytoplasm. If these fats decrease the barrier is weakened and the cell membrane becomes less permeable.

Question 19

Water will move from the soil into the root. The pressure gradient will correct for the differences in water pressure between the soil and the root. Because the pressures are both negative the “higher” value of pressure is located in the soil, therefore the water will move from the soil to the root as a way to reach equilibrium

Question 20

Fresh water fish naturally contain high levels of electrolytes in their body but at the gill level lose a lot due to the osmosis of water through the gills for gas exchange. To correct for this fish use active transport at the cellular level to retain as many electrolytes as possible. Due to the fact that fish already have an increased amount of electrolytes they would be in a state of hypertonic all the time but if active transport could not retain these electrolytes then the “solution” in the gills would become more isotonic.

Question 21

As embryos form they start with formation of a body activity. This forms in multiple layers called germ layers

A. THE ECTODERM gives rise to the central nervous system (the brain and spinal cord); the peripheral nervous system; the sensory epithelia of the eye, ear, and nose; the epidermis and its appendages (the nails and hair); the mammary glands; the hypophysis; the subcutaneous glands; and the enamel of the teeth

1. Ectodermal development is called neurulation in regard to nervous tissue

B. THE MESODERM gives rise to connective tissue, cartilage, and bone; striated and smooth muscles; the heart walls, blood and lymph vessels and cells; the kidneys; the gonads (ovaries and testes) and genital ducts; the serous membranes lining the body cavities; the spleen; and the suprarenal (adrenal) cortices

C. THE ENTODERM gives rise to the epithelial lining of the gastrointestinal and respiratory tracts; the parenchyma of the tonsils, the liver, the thymus, the thyroid, the parathyroids, and the pancreas; the epithelial lining of the urinary bladder and urethra; and the epithelial lining of the tympanic cavity, tympanic antrum, and auditory tube

1. The entoderm development is simpler than that of either mesoderm or ectoderm. It is a monocellular layer lining the yolk sac until cephalocaudal flexion of the embryo takes place

a. Flexion takes the embryo from a flat disk to its basic embryonic body form. The primitive gut originates from entoderm at the time of its flexion

b. The yolk sac constricts, thus the intraembryonic entoderm (future digestive tube) and the extraembryonic entoderm

(forms the inner lining of the yolk sac) are delineated2. Three major parts of the primitive gut are the foregut, the midgut,

and the hindgut (including the cloaca)3. The oropharyngeal (buccopharyngeal) and cloacal membranes

temporarily close the 2 ends of the primitive guta. In humans, the buccopharyngeal membrane disappears at

the beginning of week 4b. The cloacal membrane lasts longer and at week 7, like the

cloaca, it divides into an anterior urogenitalmembrane and posterior anal membrane, the latter being absorbed by week 9

If the ectoderm did not form then the nervous system would be compromised or non existent

Question 22

A polypeptide is a chain of amino acids/nucleotides, three to be exact. Polypeptide chains more multiple amino acids that make up a protein. Proteins differ based on the combinations of polypeptides and how they are folded If the final polypeptide was missing would result in a deletion of 50 nucleotides in the promoter. The promoter is where DNA transcription starts when coding a protein.

Question 23

When Methanol and water mix the hydrogen atoms in both water and methanol can be shared with the oxygen in another water and methanol combination.

Question 24

The only correct statement is that the oxygen availability is higher in a mammal environment than a fish environment. In fish, respiration takes place in their gills. Gills can collect dissolved oxygen from the water and release carbon dioxide. Gills are much more complex than just a slit in the cheek of a fish. Gills are comprised of gill arches with hundreds of gill filaments extending from them. Each filament is lined with rows of lamellae, and the gas exchange takes place as water flows through them. The frills and flaps increase the surface area to allow more gas exchange to take place, just as the alveoli do in the lungs.Fish utilize a countercurrent exchange pathway (except for cartilaginous fish),

which means that their arteries are arranged so that blood flows in the opposite direction of water movement against the gills. By having their respiration pathway in this orientation, maximum gas exchange can take place. If the blood and the water were moving in the same direction, the blood would always be next to the same bit of water which would soon be depleted of oxygen. By setting up a countercurrent pathway, the blood is always passing water that still has oxygen. This allows the blood to gather as much oxygen as it can hold.Since water must be flowing over the gills to provide a continual source of oxygen, fish have developed several ways to keep them ventilated. Some fish swim with their mouths open almost all of the time. Other fish have a special flap called an operculum, which is used to force water across the gills. The exception to all fish having gills is the lungfish, which has working lungs. It can survive when its water habitat dries up from seasonal drought. Aptly named fish. Similarly, there are also certain land crabs that use gills to breathe outside of the water.Compare to ours.

Question 25

Productivity in a food web refers to the rate of production of living material per unit of time per unit of area or volume. This would mean the largest producer would be the grass!

Question 26

Spores or zygotes encased in tough coats to resist drying out. As plants evolved from water environments to land they started with reproduction because aquatic plants used only “sperm” and “eggs” that could survive in the water. Small or occasional Water sources are found on land but usually not large enough or long enough for reproduction. The next evolution we see in plants in the development of rhizoids a very immature root or vascular tissue system that allowed plants to take in water and nutrients by diffusion and osmosis. This later developed into steam and roots that we see in plants today. The other eveolution wat seed producing plants tha used wind and fruit for seed dispersal.

Question 27

Due to the severe damage to the DNA of the cell, the DNA would not replicate. The checkpoint is a mehcnaism that is incharge of “clearing” DNA for replication. If major issues are detected it will not be replicated. Gap 0 (G0): There are times when a cell will leave the cycle and quit dividing. This may be a temporary resting period or more permanent. An example of the latter is a cell that has reached an end stage of development and will no longer divide (e.g. neuron).Gap 1 (G1): Cells increase in size in Gap 1, produce RNA and synthesize protein. An important cell cycle control mechanism activated during this period (G1 Checkpoint) ensures that everything is ready for DNA synthesis. (Click on the Checkpoints animation, above.)S Phase: To produce two similar daughter cells, the complete DNA instructions in the cell must be duplicated. DNA replication occurs during this S (synthesis) phase.Gap 2 (G2): During the gap between DNA synthesis and mitosis, the cell will continue to grow and produce new proteins. At the end of this gap is another control checkpoint (G2 Checkpoint) to determine if the cell can now proceed to enter M (mitosis) and divide.Mitosis or M Phase: Cell growth and protein production stop at this stage in the cell cycle. All of the cell's energy is focused on the complex and orderly division into two similar daughter cells. Mitosis is much shorter than interphase, lasting perhaps only one to two hours. As in both G1 and G2, there is a Checkpoint in the middle of mitosis (Metaphase Checkpoint) that ensures the cell is ready to complete cell division. Actual stages of mitosis can be viewed at Animal Cell Mitosis.Cancer cells reproduce relatively quickly in culture. In the Cancer Cell CAM compare

the length of time these cells spend in interphase to that for mitosis to occur.

Question 28

Dendrites: These structures branch out in treelike fashion and serve as the main apparatus for receiving signals from other nerve cells. They function as an "antennae" of the neuron and are covered by thousands of synapses. The dendritic membrane under the synapse (the post-synaptic membrane) has many specialized protein molecules called receptors that detect the neurotransmitters in the synaptic cleft. A nerve cell can have many dendrites which branch many times, their surface is irregular and covered in dendritic spines which are where the synaptic input connections are made. Cell bodies: The cell body (soma) is the factory of the neuron. It produces all the proteins for the dendrites, axons and synaptic terminals and contains specialized organelles such as the mitochondria, Golgi apparatus, endoplasmic reticulum, secretory granules, ribosomes and polysomes to provide energy and make the parts, as well as a production line to assemble the parts into completed products.Axons: Usually a long process which often projects to distant regions of the nervous system. The axon is the main conducting unit of the neuron, capable of conveying electrical signals along distances that range from as short as 0.1 mm to as long as 2 m. Many axon split into several branches, thereby conveying information to different targets. Many neurons do not have axons. In these so-called amacrine neurons, all the neuronal processess are dendrites. Neurons with very short axons are also found. The axons of many neurons are wrapped in a myelin sheat, which is composed of the membranes of intersticial cells and is wrapped around the axons to form several concentric layers. The myelin sheath is broken at various points by the nodes of Ranvier, so that in cross section it looks like a string of sausages. The myelin protects the axon, and prevents interference between axons as they pass along in bundles, sometimes thousands at time. The cells that wrap around peripheral nerve fibers - that is, nerve fibers outside of the brain and spinal cord - are called Schwann cells (because they were first described by Theodor Schwann). The cells that wrap around axons within the central nervous system (brain and spinal cord) are called oligodendrocytes. The axon, with its surrounded sheath, is called a nerve fiber. Between each pair of successive Schwann cells is a gap of a node of Ranvier. The axon hillock is where the axon is joined to the cell. It is from here that the electrical firing known as an action potential usually occurs. Synapses are the junctions formed with other nerve cells where the presynaptic terminal of one cell comes into 'contact' with the postsynaptic membrane of another. It is at these junctions that neurons are excited, inhibited, or modulated. There are two types of synapse, electrical and chemical. The neuronal membraneserves as a barrier to enclose the cytoplasm inside the neuron, and to exclude certain substances that float in the fluid that bathes the neuron.

The membrane with its mosaic of proteins is responsible for many important functions:

keeping certain ions and small molecules out of the cell and letting others in,

accumulating nutrients, and rejecting harmful substances, catalyzing enzymatic reactions, establishing an electrical potential inside the cell, conducting an impulse being sensitive to particular neurotransmitters and modulators . 

Question 29

In a flash flood destroys most of the burrows and only 15% of the population survives. Because the genes of only the lucky few prairie dogs that survived are passed on to the next generation their genes become “the fittest” even if they were not actually the best adapted prairie dog.

In each generation, some individuals may, just by chance, leave behind a few more descendents (and genes, of course!) than other individuals. The genes of the next generation will be the genes of the “lucky” individuals, not necessarily the healthier or “better” individuals. That, in a nutshell, is genetic drift. It happens to ALL populations—there’s no avoiding the vagaries of chance.Founder’s effect Genetic drift can cause big losses of genetic variation for small populations.Population bottlenecks occur when a population’s size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population’s genetic variation by a lot, even if the bottleneck doesn’t last for very many generations. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneckFounder effectsA founder effect occurs when a new colony is started by a few members of the original population. This small population size means that the colony may have:reduced genetic variation from the original population.a non-random sample of the genes in the original population.

Question 30

Polar refers to the hydrophilic(black) regions of proteins and non polar(white) refers to the hydrophobic regions of proteins. Knowing that the outside of the phospholipids bilayer is hydrophobic and the insides is hydrophilic, the correct arrangement of the protein is one

Question 31

Auxin are plant hormones that produce indole-3-acetic acid (IAA). It plays an important role in

development of the embryo leaf formation phototropism gravitropism apical dominance fruit development abscission root initiation and development the shade-avoidance effect

Therefore the plant will not exhibit phototropism, the growth of the plant in response to the light. Plant grow towards light source.

Question 32

Density dependent population growth: the regulation of the size of a population by mechanisms that are controlled by the size of the population and whose effectiveness increases as the population increasesDensity independent growth is when the births and deaths of a population do not affect the growth of the population.Fecundity: the reproductive rates of a population Therefore the correct answer is that population continues to grow even though the survival rate decreases.

Question 33

Cysteine will form disulfide bonds due to the avaible sulfides for bonding. Glycine will not because it has no sulfides. Both these molecules will not form hydrogen bonds

Question 34

The pedipalp. The oviduct carries vertebrate ‘s egg cells to the site of fertilizationthe vas deferens carries vertebrate sperm cells.the cloaca is a urogential opening used by egg laying vertebrates.the shell gland produces the outside layers of external eggs in vertebrates.the pedipalp are two appendages found at the head of a spider and other arthropods, used to help hold prey.

Question 35

There are three different alleles of the Xbr gene in the POPULATION but that does not mean that there are three alleles in one individual. We only receive two chromosomes, one from each parent, and since all these alleles are found on one

chromosome, we only receive 2 copies of this geneQuestion 36

Fermentation is the metabolic process that occurs when converting sugar to acids, gases, and or alcohol. It occurs in species like yeasts and bacteria.Only glycolysis occurs in organisms that undergo fermentation, resulting in less ATP production than those that use cellular respiration (the citric acid cycle, electron transport chain), therefore leaving less energy for growth.

Question 37

Lysosomes: membrane-enclosed organelles that contain an array of enzymescapable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids. Lysosomes function as the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself. In their simplest form, lysosomes are visualized as dense spherical vacuoles, but they can display considerable variation in size and shape as a result of differences in the materials that have been taken up for digestion. Lysosomes thus represent morphologically diverse organelles defined by the common function of degrading intracellular material.phagosome is a vesicle formed around a particle absorbed by phagocytosis. The vacuole is formed by the fusion of the cell membrane around the particle.Mitochondria play a critical role in the generation of metabolic energy ineukaryotic cells. As reviewed in Chapter 2, they are responsible for most of the useful energy derived from the breakdown of carbohydrates and fatty acids, which is converted to ATP by the process of oxidative phosphorylation. Most mitochondrial proteins are translated on free cytosolic ribosomes and imported into the organelle by specific targeting signals. In addition, mitochondria are unique among the cytoplasmic organelles already discussed in that they contain their own DNA, which encodes tRNAs, rRNAs, and some mitochondrial proteins. The assembly of mitochondria thus involves proteins encoded by their own genomes and translated within the organelle, as well as proteins encoded by the nuclear genome and imported from the cytosol.vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protist,animal [1] and bacterial cells.[2] Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules includingenzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these.[3] The organelle has no basic shape or size; its structure varies according to the needs of the cell.

1. Peroxisomes are small, membrane-enclosed organelles that contain enzymes involved in a variety of metabolic reactions, including several aspects of energy metabolism.

Question 38

Where the lines matchup is where the child has genes in common with the individuals. All gene fragments in the child must match the mother or the father. Male one could be the father.electrophoresis is a method for separation and analysis of DNA, RNA and proteins and their fragments, based on their size and charge. It is used inMolecular bio to separate a mixed population of DNAand RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge. Nucleic acid molecules are separated by applying an electric field to move the fragments of DNA. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving. Proteins are separated by charge in agarose because the pores of the gel are too large to sieve proteins. Gel electrophoresis can also be used for separation of nanoparticles.A combination of enzymes are used to cut the DNA samples in certain places or nucleotide cominbations. In this scenario if an individual is related to two of the sample of individuals being tested we would expect to see the enzyme make the same or similar cut in the DNA in terms of size.

Question 39

The rules for speciation or what makes a two groups of similar animals different species is:

The offspring between a member from one species and another will be sterile or not viable, breeding issues

Some appearance, location/environment responses

Question 40

Autosomal Recessive Disease: is a disorder that is only present when two recessive alleles are present, otherwise it is mask by the dominant normal conditionBoth Parents are Aa because: to have unaffected and affected children and for the parents to be unaffected as well the only possible combination of genotypes is Aa.

A aA AA Aaa Aa aa

Question 41

Neurons send messages electrochemically. This means that chemicals cause an electrical signal. Chemicals in the body are "electrically-charged" -- when they have an electrical charge, they are called ions. The important ions in the nervous system are sodium and potassium (both have 1 positive charge, +), calcium (has 2 positive charges, ++) and chloride (has a negative charge, -). rest, potassium ions (K+) can cross through the membrane easily. Also at rest, chloride ions (Cl-)and sodium ions (Na+) have a more difficult time crossing. The

negatively charged protein molecules (A-) inside the neuron cannot cross the membrane. In addition to these selective ion channels, there is a pump that uses energy to move three sodium ions out of the neuron for every two potassium ions it puts in.An action potential occurs when a neuron sends information down an axon, away from the cell body. Action potentials are caused when different ions cross the neuron membrane. A stimulus first causes sodium channels to open. Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. Remember, sodium has a positive charge, so the neuron becomes more positive and becomes depolarized. It takes longer for potassium channels to open. When they do open, potassium rushes out of the cell, reversing the depolarization. The effect of preventing the flow of potassium ions would be that the neuron would never repolarize due to the inability of potassium to rush out of the cell.

Question 42

a. Interspecific competition: individuals of different species compete for the same resource in an ecosystemb. Mutualism: two organisms of different species exist in a relationship in which each individual benefits from the activity of the other. c. Parasitism: non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host.d. Commensalism: two organisms where one organism benefits from the other without affecting it.e. Predation: a predator (an organism that is hunting) feeds on its prey (the organism that is attacked)

Question 43

1. Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic linkages and on hydrolysis give the constituent monosaccharides or oligosaccharides. They range in structure from linear to highly branched. An example is cellulose in plant, it is difficult of ruse to digest i.e. it takes more time.The answer is D, The parallel strands of cellulose that are joined by hydrogen bonds provide support in the cell walls of plants.

Question 44

Trisomy: a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. The number 21 refers to the number of the chromosome pair that has an additional copy, this leads to down’s

syndrome and occurs in one of three ways, an extra copy is received from mom, or dad or occurs when the sperm and egg meet. The Egg or sperm of this mouse will be a mix of normal gametes and gametes with an extra copy of 21, because the three chromosomes will note separate evenly.Answer is C.

Question45

The most affected area will the citric acid cycle which means that the electron carriers FADH2 will be affected but not converted back FAD, they will not produce citrate meaning that he electron transport chain will be unable to phosphoylate ADP to ATP. Answer A

Question 46

a. Mutation: a genetic variation from normal or genes that were already part of the genetic makeup of an individualb. Genetic drift: the change in the frequency of a gene variant (allele) in a population due to random sampling of organisms.c. Immigration: the movement of species into an area to which they are not native in order to settle there, especially as permanent residents d. Non-random mating: which individuals with similar genotypes and/or phenotypes mate with one another more frequently than would be expected under a random mating patterne. Natural selection: survival of the fittest, fittest meaning best suited for conditions of an environment and survival meaning ability to reproduceAnswer B

Question47

a. Diffusion: the movement of particle across a membrane from an area of high to low concentration or using a gradient to reach equilibriumb. Osmosis: the movement of water across a membrane from an area of high to low concentration or using a gradient to reach equilibriumc. Facilitated diffusion: the process of spontaneous passive transport(as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.d. Active transport: the use of energy to move particles against a concentration

gradient ex. Na-K Pumpe. Receptor mediated transport: process by which cells absorb molecules (endocytosis) by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being absorbed.The answer is A because the particles are moving because of gradient created on either side of the membrane

Question48 a. cytotoxic T cell: hat kills cancer cells, cells that are infected (particularly

with viruses), or cells that are damaged in other ways. Most cytotoxic T cells express T-cell receptors (TCRs) that can recognize a specific antigen

b. A B cell: a lymphocyte not processed by the thymus gland, and responsible for producing antibodies

1. c. A helper T cell: a T cell that influences or controls the differentiation or activity of other cells of the immune system.d. A neutrophil, a type of white blood cell: Neutrophils are a type of phagocyte and are normally found in the bloodstream. During the beginning (acute) phase of inflammation, particularly as a result of bacterial infection , environmental exposure,[4] and some cancers,[5][6] neutrophils are one of the first-responders of inflammatory cells to migrate towards the site of inflammatione. A memory cell: are important in generating an accelerated and more robust antibody-mediated immune response in the case of re-infection (also known as a secondary immune response).Answer is D, only phagocyte immunoreponsive white blood cell.

Question49

Terrestrial native species are species that’s original habitats where on land in certain location. Therefore the loss of habitat due to human activity would be the main cause for their decrease. Answer B

Question 50

G-C bonds have three hydrogen bonds and A-T bonds have two. The result is the more G-C pairs there are the higher the temp needed to Denature DNA. However the more base pairs needed to denature the higher the temperature needed to cause that denature. Due to having twice as many base pairs to denature Molecule three will require the highest temperature to Denature the DNA strand.