Biology PSSA Prep Mrs. Jeffers
“Biology is the only science in which multiplication is
the same thing as division.”
Designed by Jackie Jeffers
With modifications by Barb Eisel & Theresa Banas
I. Levels of Organization
Cellular Level:
! Draw a unicellular and a multicellular organism
! 25. Which shows the correct sequence of organization in mlticellular organisms?
A. cell, organ, tissue, organ system B. Tissue, cell, organ, organ system C. Cell, tissue, organ, organ system D. Organ, organ system, tissue, cell
Levels of Structural Organization
Figure 1.1, step 1
Molecules Atoms
Chemical level Atoms combine to form molecules
Levels of Structural Organization
Figure 1.1, step 2
Smooth muscle cell Molecules Atoms Cellular level
Cells are made up of molecules Chemical level
Atoms combine to form molecules
Levels of Structural Organization
Figure 1.1, step 3
Smooth muscle cell Molecules Atoms
Smooth muscle tissue
Cellular level Cells are made up of molecules
Tissue level Tissues consist of similar types of cells
Chemical level Atoms combine to form molecules
Levels of Structural Organization
Figure 1.1, step 4
Smooth muscle cell Molecules Atoms
Smooth muscle tissue
Cellular level Cells are made up of molecules
Tissues consist of similar types of cells
Organ Organs are made up of different types of tissues
Chemical level Atoms combine to form molecules
Levels of Structural Organization
Figure 1.1, step 5
Smooth muscle cell Molecules Atoms
Smooth muscle tissue
Cardio- vascular system
Cellular level Cells are made up of molecules
Tissue level Tissues similar types of cells
Organ level Organs are made up of different types of tissues
Organ system level Organ systems consist of different organs that work together closely
Chemical level Atoms combine to form molecules
! Features of Life?
Figure 1.2a
Human Homeostasis: Organ System Overview
! Integumentary (Skin) ¶ Forms the external body
covering ¶ Protects deeper tissue
from injury
¶ Helps regulate body temperature
Figure 1.2b
Organ System Overview
! Skeletal ¶ Protects and supports
body organs ¶ Provides muscle
attachment for movement ¶ Site of blood cell
formation ¶ Stores minerals
Figure 1.2c
Organ System Overview
! Muscular ¶ Produces movement ¶ Maintains posture ¶ Produces heat
Organ System Overview
! Nervous ¶ Fast-acting control
system ¶ Responds to internal and
external change ¶ Activates muscles and
glands Figure 1.2d
Organ System Overview
! Endocrine ¶ Secretes regulatory
hormones ! Growth ! Reproduction ! Metabolism
Figure 1.2e
Figure 1.2f
Organ System Overview
! Cardiovascular ¶ Transports materials in body
via blood pumped by heart ! Oxygen ! Carbon dioxide ! Nutrients ! Wastes
Organ System Overview
! Lymphatic ¶ Returns fluids to blood
vessels ¶ Cleanses the blood ¶ Involved in immunity
Figure 1.2g
Organ System Overview
! Respiratory ¶ Keeps blood supplied with
oxygen ¶ Removes carbon dioxide
Figure 1.2h
Organ System Overview
! Digestive ¶ Breaks down food ¶ Allows for nutrient
absorption into blood ¶ Eliminates indigestible
material
Figure 1.2i
Organ System Overview
! Urinary ¶ Eliminates nitrogenous
wastes ¶ Maintains acid-base
balance ¶ Regulates water and
electrolytes Figure 1.2j
Interrelationships Among Body Systems
Figure 1.3
Homeostasis
! Homeostasis—maintenance of a stable internal environment ¶ A dynamic state of
equilibrium ! Homeostasis is necessary
for normal body functioning and to sustain life
! Homeostatic imbalance ¶ A disturbance in
homeostasis resulting in disease
Figure 1.4, step 1a
Variable (in homeostasis)
Figure 1.4, step 1b
Stimulus: Produces change in variable Variable
(in homeostasis)
Figure 1.4, step 2
Change detected by receptor
Stimulus: Produces change in variable
Receptor (sensor)
Variable (in homeostasis)
Figure 1.4, step 3
Change detected by receptor
Stimulus: Produces change in variable
Input: Information sent along afferent pathway to
Receptor (sensor)
Variable (in homeostasis)
Control center
Figure 1.4, step 4
Change detected by receptor
Stimulus: Produces change in variable
Input: Information sent along afferent pathway to
Receptor (sensor) Effector
Variable (in homeostasis)
Output: Information sent along efferent pathway to activate
Control center
Figure 1.4, step 5
Change detected by receptor
Stimulus: Produces change in variable
Input: Information sent along afferent pathway to
Receptor (sensor) Effector
Variable (in homeostasis)
Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis
Output: Information sent along efferent pathway to activate
Control center
Maintaining Homeostasis
! The body communicates through neural and hormonal control systems ¶ Receptor
! Responds to changes in the environment (stimuli)
! Sends information to control center
Maintaining Homeostasis
¶ Control center (nervous & endocrine systems) ! Determines set point ! Analyzes information ! Determines appropriate response
¶ Effector ! Provides a means for response to
the stimulus
Feedback Mechanisms
! Negative feedback ¶ Shuts off the original
stimulus, or reduces its intensity
¶ Works like a household thermostat
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Biochemistry Covalent Bonds Share Electrons Most Common Bond in Organic Compounds
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9. Water is the universal solvent because it is polar with uneven sharing of electrons causing ends to be oppositely charged.
8. Non polar molecules do not have charges on the ends. Equal sharing of electrons. Do not dissolve in water.
Water Properties
! Cohesion ! Adhesion/Capillarity ! High specific heat
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Carbohydrates ! Carbohydrates are
organic compounds made of carbon, hydrogen and oxygen.
! They are the key source of energy for all cells.
Lipids ! Nonpolar molecule
that are not soluble or mostly insoluble in water.
! Includes fats, phospholipids, steroids and waxes.
! Important part of the structure and function of cell membranes.
! Store energy
Proteins ! A protein is a large
molecule made by linking together smaller molecules called amino acids.
! Almost all life processes of a cell involve proteins which make up the structure and regulate the function of living things.
Enzymes ! Speed up chemical reactions by lowering
the activation energy. ! Made of proteins ! Bind with molecules (substrate) at the
active site (Lock & key fit) ! Not part of chemical reactions. ! Can be inactivated by changes in pH or
temperature (active site changes shape)
II. Classification
Taxonomy
! Species- ¶ a group of organisms
that share similar characteristics and can interbreed to produce fertile offspring
Hierarchy- Taxonomic Groups
Domain Kingdom Phylum (Division – used for plants) Class Order Family Genus Species
BROADEST TAXON
Domains:
! 3 Domains: Bacteria, Achaea, Eukarya ¶ Bacteria & Archaea –
(Prokaryotic cells)
¶ Eukarya- (Eukaryotic cells) protists, fungi, plantae, animalia
Cells
! Draw a prokaryotic cell and a eukaryotic cell
Overview ! Cell membrane separates living cell from
nonliving surroundings ! Controls traffic in & out of the cell
¶ selectively permeable ¶ allows some substances to cross more easily
than others ! hydrophobic vs hydrophilic
! Made of phospholipids, proteins & other macromolecules
More than lipids… ! In 1972, S.J. Singer & G. Nicolson proposed that
membrane proteins are inserted into the phospholipid bilayer
It’s like a fluid… It’s like a mosaic… It’s the Fluid Mosaic Model!
Membrane is a collage of proteins & other molecules embedded in the fluid matrix of the lipid bilayer
Extracellular fluid
Cholesterol
Cytoplasm
Glycolipid
Transmembrane proteins
Filaments of cytoskeleton
Peripheral protein
Glycoprotein
Phospholipids
Many Functions of Membrane Proteins Outside
Plasma membrane
Inside Transporter Cell surface
receptor Enzyme activity
Cell surface identity marker
Attachment to the cytoskeleton
Cell adhesion
2007-2008
Movement across the Cell Membrane
Diffusion ! Move from HIGH to LOW concentration
¶ “passive transport” ¶ no energy needed
diffusion osmosis
movement of water
Channels through cell membrane
! Membrane becomes semi-permeable with protein channels ¶ specific channels allow specific material
across cell membrane
inside cell
outside cell
sugar aa H2O
salt NH3
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FACILITATED DIFFUSION: The diffusion of material through a channel in the plasma membrane.
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Characteristics of Active Transport: 1. Can move LARGE molecules across the plasma membrane. example: glucose 2. Can move against the diffusion gradient - LOW to HIGH concentration requiring energy. 3. Sodium Potassium Pump, Endocytosis, Exocytosis.
III. Photosynthesis & Respiration
Photosynthesis:
6CO2 + 6H2O (light energy) C6H12O6 + 6O2
• Chloroplasts • Chlorophyll • Requires ATP
Respiration C6H12O6 + 6O2 6CO2 + 6H2O +
Energy (ATP) Three pathways: • Glycolysis
• (changes sugar to pyruvic Acid)
• Krebs Cycle • Electron Transport chain Both Plants & Animals carry out
respiration
Cellular Respiration Total Energy Production:
¶ Glycolysis – 2 ATP’s
¶ Krebs Cycle- 2 ATP’s
¶ Electron Transport- 32 ATP’s
Total ATP output: 36 ATP
! What are the two forms of reproduction and how do they differ?
! What are the two forms of reproduction and how do they differ?
A. Asexual Reproduction
! Single cell divides ! Produces 2 new cells ! Exact # of chromosomes ¶ Offspring identical to
parent
¶ Budding in fungi
¶ Binary Fission in Bacteria
B. Sexual Reproduction
! Requires two specialized cells- “Gametes” ¶ Meiosis- production of
gametes
VI. Mitosis & Meiosis
Prokaryotic Cell Division
¶ Binary fission ! DNA copied ! Cell divides into two cells ! Daughter cell is exactly like
parental cell
Binary Fission
Eukaryotic Cellular Division
! Cell Cycle ¶ Cell grows
¶ Chromosomes copied
¶ 2 Daughter cells formed
! Phases of the Cell Cycle: ! 1. Interphase- most of the cells lifecycle is spent in Interphase ¶ Three phases:
! G1 ! S (synthesis) ! G2
! G1 ¶ Cell increases in size
¶ Organelles double
¶ New cytoplasm forms
! S (synthesis) phase: ¶ Chromosomes replicate
! 2 identical stands “sister chromatids” o Joined together at the centromere
! G2 Phase: ¶ Second growth phase
¶ Cell is now ready for Mitosis
! 2. Mitosis- ¶ nucleus divides
¶ Production of Diploid Cells (full number of chromosomes ! 46 – 46 ! 10-10
! Four stages: ¶ A. prophase
¶ B. Metaphase
¶ C. Anaphase
¶ D. Telophase The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.
! A. Prophase: ¶ Nucleus breaks down
¶ Spindle fibers attach to centromeres
¶ Centrioles move to opposite poles
! B. Metaphase: ¶ Sister chromatids line up
along the equator of the cell
! C. Anaphase ¶ Spindle fibers pull sister
chromatids apart
¶ Spindle fibers pull chromatids to opposite ends of the cell
! D. Telophase ¶ Spindle fibers disappear
¶ Nuclear membranes form (2 nuclei)
! Cytokinesis- division of cell cytoplasm ¶ New cell membrane
forms (plants: cell wall)
¶ Membrane pinches off
¶ Result is two new daughter cells
Meiosis
! Production of Haploid Cells (½ # of chromosomes)
! 46 – 23 10- 5
! Production of Gametes (sex cells) ¶ Male: Sperm
¶ Female: Ova ! Each have ½ # chromosomes
! Comprised of two parts, two cellular divisions: ¶ Meiosis I
¶ Meiosis II
! Results in 4 genetically different cells
! 1 Diploid cell 4 Haploid cells
Meiosis I
! Four stages: ¶ Prophase I
¶ Metaphase I
¶ Anaphase I
¶ Telophase I / Cytokinesis I
! Prophase I ¶ Synapsis occurs-
! homologous chromosomes pair up (form tetrad)
¶ Crossing –over occurs ! Genetic material exchanged
! Metaphase I ¶ Independent assortment
occurs ! Homologous pairs line up in
center
! Anaphase I ¶ Spindle fibers separate
homologous chromosomes
! Telophase I- ¶ Results in 2 Diploid cells
that are genetically different from one another
Meiosis I
Meiosis II
! Four stages ¶ Prophase II
¶ Metaphase II
¶ Anaphase II
¶ Telophase II
*Identical to mitosis
Meiosis II
! Results in four haploid cells ¶ Each with unique
chromosomes
Meiosis II
! Remember: Meiosis occurs in the Sex Cells; Mitosis occurs in all other cells
IV. DNA Replication & Protein Synthesis
! Two Types of Nucleic Acids: ¶ DNA- deoxyribonucleic
acid
¶ RNA- ribonucleic acid
Structure of DNA:
! Draw a strand of DNA
Structure of DNA
¶ Three parts: ! Sugar ! Phosphate ! Nitrogen base- Adenine, Thymine,
Guanine & Cytosine
¶ Double helix ! Sugar & phosphate backbone ! Nitrogen bases make up the rungs
Ribonucleic Acid
! RNA: ¶ Single stranded
¶ Sugar is ribose
¶ Contains Uracil (no thymine)
DNA Replication
¶ Occurs before cellular division- Why?
¶ Process:
! DNA unzipped by enzyme helicase ! Complementary base pairing and
proofreading by DNA polymerase o A-T T-A o G-C C-G
DNA:
What would be the complimentary strand for: ACG TAA CGG TAA? TGC ATT GCC ATT
DNA Mutations
! Missense mutation = Base substitutions that cause replacement of one or more amino acids. Can negatively effect protein function or can be undetectable (silent)
DNA Mutations
! Nonsense mutations = base substitutions that delete an amino acid and terminate protein synthesis. Usually destroys the function of the protein.
DNA Mutations
! Frame shift = insertion or deletion of one or two bases. Shifts reading frame of codons.
DNA Mutations
! Translocation= part of one chromosome becomes attached to another.
! Inversion = segment of DNA breaks off, then reinserts in reverse.
Protein Synthesis
! Transcription & Translation ¶ Production of Proteins-
large organic molecules ! Building blocks of cells
¶ Amino Acids ! Building blocks of proteins
Transcription
! Occurs in the Nucleus: ¶ Production of RNA
! Instructions for making proteins
¶ DNA unzips
Transcription
¶ Complementary RNA nucleotides lay down ! A-U, T-A, C-G, G-C ! Arranged in sequences of 3-
“Codons” o Codes for amino acids o Process controlled by enzyme RNA
polymerase
U = Uracil
Messenger RNA
! A strand of DNA has the following sequence:
TCT GAT AAG ATC What sequence of bases will make up the strand of mRNA?
AGA CUA UUC UAG
! mRNA: AGA CUA UUC UAG What amino acids does this strand code for?
mRNA Codon - Amino Acid Table
Amino Acids:
! A strand of mRNA has the following sequence:
AGA CUA UUC UAG What amino acids does this strand code for?
Arg, leu, phe, Stop!
Translation
! Occurs in the cytoplasm ! “Translation” of the mRNA
! From mRNA to Amino Acids
¶ Ribosomes ! rRNA – produces proteins ! tRNA- carries amino acids to build
proteins
¶ Peptide Chain ! Chain of amino acids ! Twists to form proteins
www.columbia.edu/.../c2005/lectures/lec14_08.pdf
Genes & traits
! Gene- ¶ section of chromosome
that codes for a trait
! Allele- ¶ An
Alternate
form of a
gene.
! Homologous Chromosomes- ¶ similar in size, shape & genetic
material
! Chromosome # varies among organisms ¶ Human- 46
¶ Cat – 32
¶ Dog – 78
¶ Mosquito- 6
¶ Corn - 20
Alleles
! Dominant- ¶ expresses its trait over
all other traits
¶ Represented by a capital letter ! AA, BB, TT, etc.
! Recessive- ¶ expresses its trait ONLY
in the absence of a dominant allele
¶ Represented by small letters ! aa, tt, bb, etc.
! Homozygous- ¶ Receives two dominant
or two recessive alleles ! AA, BB, tt, rr
! Heterozygous- ¶ Receives one dominant
and one recessive allele ! Aa, Bb, Tt
! Genotype- ¶ The alleles that an
organism actually receives: ! TT, Tt, tt, AA, Aa, aa
! Phenotype- ¶ The traits that an
organism exhibits: ! TT = Tall ! Tt = Tall ! tt- = short
Predicting Genotype & Phenotype
! Punnett Square ¶ predicts the probability
of the offspring's genotype and phenotype ! Monohybrid cross- looking at one
trait ! Dihybrid cross- looking at two
traits
! In pea plants, round (R) seeds are dominant over wrinkled (r) seeds. Use a Punnett Square to set up a cross between two parents that are heterozygous for round seeds. (monohybrid cross)
R r
R
r
Genotypes: ¼ = RR ½ = Rr ¼ = rr Phenotypes: ¾ = Round ¼ = Wrinkled
P1 Cross:
RR Rr
Rr rr
! Using offspring from the F1 generation, cross a homozygous dominant with a homozygous recessive
R R
r
r
Genotypes: 4/4, 100% = Rr Phenotypes: 4/4, 100% = Round
F1 Cross:
Rr Rr
Rr Rr
! Show a Dihybrid cross of two heterozygous individuals to examine pod color and seed color. Green pods (G) are dominant over yellow pods (g) and yellow seeds (Y) are dominant over green seeds (y)
GY Gy gY gy
GY GGYY GGYy GgYY GgYy
Gy GGYy Ggyy GgYy Ggyy
gY GgYY GgYy ggYY ggYy
gy GgYy Ggyy ggYy ggyy
Gg Yy Gg Yy X
VII. Patterns of Inheritance
GY Gy gY gy
GY GGYY GGYy GgYY GgYy
Gy GGYy Ggyy GgYy Ggyy
gY GgYY GgYy ggYY ggYy
gy GgYy Ggyy ggYy ggyy
Law of Independent Assortment
! Notice that the gene for one trait does not affect whether the gene of
another trait is inherited.
! The Law of Independent Assortment states that genes for traits found on different chromosomes separate independently when gametes are formed
Other Patterns of Inheritance
! Incomplete dominance ¶ Trait is
between the phenotypes of its parents ! Cross a red flower
with a white flower, all offspring are pink
! Codominance ¶ Both alleles are
expressed ! Cross a red flower with a white
flower, offspring are both red & white
! Multiple alleles ¶ Genes that have more
than two alleles for a trait ! Human blood type- A,B, & O
! Polygenic traits ¶ Traits influenced by more than one
gene
¶ Genes may be located on different chromosomes or at different positions on the same chromosome
! Skin, eye color, hair, etc.
Expression is influenced by environmental factors
Sex-Linked Traits
! Autosome- any chromosome that is not a sex chromosome
! Sex chromosome- X & Y chromosmes ¶ Determine the sex of the
individual ! XX = female XY = male
! Sex-Linked traits ¶ Traits located on the X
or Y chromosome
! X-Linked traits ¶ Typically recessive
¶ Male with recessive X, will have the trait
Colorblindness
C
Problem: ! Hermansky-Pudlak syndrome,
Albinism, is a sex-linked recessive disease.
! A heterozygous female marries a man that has the disease……
Albinism
X Y
X
X
a
A XAXa XAY
XaXa XaY a
Pedigree
! Pedigree- ¶ a diagram that shows
how a trait is inherited over generations ! Used to track sex-linked traits ! Squares = males, Circles =
females
Genetic Variations in Populations
Mutations & Variation
! Variation- ¶ differences in traits
among members of a population
Mutations & Variation
! Fitness- ¶ The ability to pass
desirable traits onto offspring in order for the continuation of the species.
Natural Selection
Change in Species
! Adaptations- ¶ any trait that improves an
organism’s chance for survival & reproduction
! Natural Selection is a scientific theory that explains the process of evolution.
! Based on Four Principles:
! 1. Variation exists within populations
! 2. Organisms compete for limited natural resources.
! 3. Organisms produce more offspring than can survive
! 4. Individuals with variations suitable for their habitat survive and reproduce.
! Biodiversity- ¶ variety in the number of
different kinds of species living on Earth
! Extinction- ¶ occurs when there are
no longer any members of a living species on Earth
! Mass Extinction- ¶ occurs when huge
numbers of species die out in a fairly short period of time.
Variations affect the Genetic Makeup of a population
! Natural Selection- ¶ only the most fit and
those most adapted to their environment will survive & reproduce
! Stabilizing selection- eliminates those that have extreme traits
! Directional Selection- individuals at one end of the frequency distribution are better adapted to the environment than those in the middle
! Disruptive Selection- individuals at the extreme ends of the distribution are better adapted than those in the middle
Speciation ! Species-
¶ group that share similar characteristics that interbreed to produce fertile offspring
! Population- ¶ all the members of a
species that live in the same area at the same time
! Speciation- ¶ evolution of a new
species from an existing species. Ex: Finch Beaks ! Geographic isolation ! Parapatric speciation ! Behavioral isolation
! Geographic Isolation- ¶ population is divided by a
physical barrier into two geographically isolated populations. ! Differences become so great, they
can no longer interbreed
! Parapatric speciation- ¶ neighboring populations
live in different environments ! Hot, Dry env. Vs cold, wet ! Two pop. become genetically
different
! Behavioral isolation- ¶ differences in courtship
rituals or other types of behaviors ! Choose different mates ! Leads to genetically different
individuals
Evolution in species
! Gradual evolution = slow, steady change in a population to adapt.
! Punctuated = sporadic changes, with long periods where no evolution occurs. Fits fossil records
Evolution in related species
! Convergent vs divergent
Question #1
! Based on a picture of Finch beaks and Darwin’s observations, which of the following best explains the differences in beak shapes?
A. The different finch species have migrated and separated to their own islands to minimize competition.
B. At some point in the past, the small tree finch must have bred with the cactus finch to create the vegetarian finch species.
C. Each species developed beaks that made it easier to obtain the food they most liked to eat.
D. Through adaptation, the species of finches have developed beaks that are better suited to the different foods available on their island.
Evolutionary Relationships
! Phylogeny: ¶ study of evolutionary
history of related species ! Phylogenic Tree
Fossil Evidence -
Comparative Anatomy
! Examine similar structures: ¶ Homologous Structures
¶ Analogous Structures
¶ Vestigial Structures ! Ex: Rat appendix vs human
appendix
Indicate shared ancestry
Homologous structures: Similar structure, differ in function
Analogous Structures: Similar function, differ in structure
! Examine embryology ¶ Embryo- early stage in
the development of an organism
! Examine Chemical components ¶ Sequence of nucleotides
¶ Sequence of amino acids
Question #4 ! An unknown organism is discovered in an
African tropical rainforest. The scientist describes it as multicellular,(nucleus, cell membrane, no cell wall or chloroplasts). Into which of the following kingdoms is the scientist most likely to place this organism?
A. Protista B. Animalia C. Fungi D. Plantae
Question: ! Scientists compare a fossil bird wing to the
structures making up a human arm and a whale flipper. They observe that the number and arrangement of bones in the forelimbs of all three animals are very similar. What does this finding suggest about the three animals?
! A. They do not share a common ancestor. ! B. They share a common ancestor. ! C. They are all capable of using their
forelimbs for flight. ! D. they are all invertebrates.
Technology & Genetic Variation
! Selective Breeding- ¶ allowing only organisms
with specific traits to reproduce ! Ex: show dogs, race horses
! Biotechnology- ¶ using organisms for
practical purposes ! Perform certain tasks’ *Recombinant bacteria produce medicines like insulin
Biotechnology- using organisms for practical purposes
! Genetically modified organisms
Improved food crops and livestock
Biotechnology- using organisms for practical purposes
! Gene therapy Replacing genes for diseases with healthy versions in the future
Biotechnology- using organisms for practical purposes
! Genetic testing and counseling for genetic disorders
! Stem cell therapy for treatments of diseases and injuries
DNA Fingerprinting
! DNA is cut into segments by restriction enzymes
! Segments are separated according to size by gel electrophoresis
! Creates unique barcode or “fingerprint” pattern
! http://highered.mcgraw-hill.com/sites/dl/free/0072835125/126997/animation40.html
! Genetic Engineering- ¶ genes or pieces of DNA are
taken from one organism and transferred to another organism ! Recombinant DNA-when 2 pieces of
DNA from different organisms join together
! Cloning- ¶ genetically identical
individuals are created from a single cell