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Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the...

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Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents
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Page 1: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Cellular Reproduction and DNA

Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents

Page 2: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Cellular Reproduction and DNA

Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents

Lamarkian biology- characteristics such as height, strength, and weight are determined by the activities of the parents. (FAIL.)

Page 3: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

The Father of Modern Genetics

Gregor Mendel (1822-1884): an Austrian monk

Gave first real explanation for how traits are passed on to offspring

Conducted meticulous experiments on 29,000 pea plants

Mendel's work was rejected during his lifetime, and it wasn't widely accepted until the 1930's and 1940's

Genetics- the science that studies how characteristics get passed from parent to offspring

Page 4: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genes, Chromosomes, and DNADNA governs an organism's

traits and characteristics

DNA's main function is to tell the cell what proteins to make

Page 5: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genes, Chromosomes, and DNADNA governs an organism's

traits and characteristics

DNA's main function is to tell the cell what proteins to make

Not every organism's traits are completely determined by a person's genes

Genetic tendency- a range of possible characteristics set by DNA

Page 6: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genetic Tendencies People have a certain capacity for musical ability, or athletic ability

Some people choose to fight against genetic predispositions such as alcoholism and obesity

Consider an alcoholic whose father is also an alcoholic- you could argue that the son learned this through father, or that alcoholism is in his genes, or it's a combination of both

Page 7: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genetic Tendencies People have a certain capacity for musical ability, or athletic ability

Some people choose to fight against genetic predispositions such as alcoholism and obesity

Consider an alcoholic whose father is also an alcoholic- you could argue that the son learned this through father, or that alcoholism is in his genes, or it's a combination of both

Gay rights activists are searching for a “gay gene” in order to justify their behavior

However, many defects are transmitted through genes (eg. Down Syndrome, cystic fibrosis, color blindness)

Even if a “gay gene” were found, a gene cannot force a person into a homosexual lifestyle- he is able to choose how to live, just like an alcoholic can choose not to drink alcohol

Page 8: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Developmental Factors

Characteristics completely from DNA: hair color, blood type

DNA alone does not determine who you are or what you will become

DNA provides the general framework within which you decide who you will become

Page 9: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Characteristics completely from DNA: hair color, blood type

DNA alone does not determine who you are or what you will become

DNA provides the general framework within which you decide who you will become

Genetic factors- traits determined by DNA

Environmental factors- nonbiological factors that are involved in a person's surroundings (family, friends, school, choices they make)

Spiritual factors- factors in a person's life determined by the quality of their relationship with God

There is still much debate over how much influence each of these factors has over a person's development

Developmental Factors

Page 10: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genes and DNA

Gene- a section of DNA that codes for the production or portion of protein, thereby causing a trait

Page 11: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genes and DNA

Gene- a section of DNA that codes for the production or portion of protein, thereby causing a trait

The tasks that a cell can complete depend upon the proteins it produces

If a cell produces certain proteins, it's a nerve cell, if it make other proteins, it's a blood cell

Page 12: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Genes and DNA

Gene- a section of DNA that codes for the production or portion of protein, thereby causing a trait

The tasks that a cell can complete depend upon the proteins it produces

If a cell produces certain proteins, it's a nerve cell, if it make other proteins, it's a blood cell

A cell knows what proteins it should produce because the DNA tells it what to make

Page 13: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

DNA and RNA

Page 14: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

DNA and RNA

DNASugar: deoxyribose

Structure: double helix

Nucleotides: adenine, guanine, cytosine, thymine

More stable, less likely to experience changes during duplication (less mutations)

RNA

Sugar: ribose

Structure: single strand

Nucleotides: adenine, guanine, cytosine, thymine

Less stable

Page 15: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part 1: Transcription

1. Transcription- building an RNA strand from a section of DNA

RNA copies DNA by attaching corresponding nucleotide bases

RNA is like a camera that produces a negative image (light in places it should be dark)

T- A

C- G

A- U

Page 16: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: Translation

2. Translation: the process of translating the nucleotide bases into amino acid sequences

Page 17: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: Translation

2. Translation: the process of translating the nucleotide bases into amino acid sequences

Messenger RNA (mRNA)- RNA that performs transcription and then goes to the ribosomes

Page 18: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: Translation

2. Translation: the process of translating the nucleotide bases into amino acid sequences

Messenger RNA (mRNA)- RNA that performs transcription and then goes to the ribosomes

Transfer RNA (tRNA)- contains an anticodon bonded to an amino acid

Anticodon- three nucleotide base sequence on tRNA

Page 19: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: TranslationCodon- a sequence of three

nucleotide bases on mRNA that refers to specific amino acid

Page 20: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: TranslationCodon- a sequence of three

nucleotide bases on mRNA that refers to specific amino acid

Translation repeats until all amino acids that are called for by codons are linked together

DNA → RNA → protein

Page 21: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Protein Synthesis- Part II: TranslationCodon- a sequence of three

nucleotide bases on mRNA that refers to specific amino acid

Translation repeats until all amino acids that are called for by codons are linked together

DNA → RNA → protein

A given amino acid can be “called for” by several different codons. eg. cysteine can be called by UGC or UGU

However, a single codon cannot call for more than one amino acid (eg. UGU is only for cysteine)

Protein Synthesis

Page 22: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

DNA and RNAExons- part of DNA with instructions for making a protein

Introns- separates exons, must be removed before it becomes mRNA

Page 23: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

DNA and RNAExons- part of DNA with instructions for making a protein

Introns- separates exons, must be removed before it becomes mRNA

Introns are also known as “junk DNA” because they don't appear to serve any purpose

DNA is very thin- .0000002mm

If all the DNA from one cell we strung together end to end, it would be six feet long. All DNA in body: 67 billion miles (16x distance of Pluto to Sun)

Page 24: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

How DNA is Packaged

Histones- proteins that act as spools which wind up small stretches of DNA

Nucleosomes- beads of DNA wrapped around histone

Page 25: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

How DNA is Packaged

Histones- proteins that act as spools which wind up small stretches of DNA

Nucleosomes- beads of DNA wrapped around histone

Chromosome- network of DNA coils and proteins

In nucleus

Page 26: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

How DNA is PackagedHistones- proteins that act as

spools which wind up small stretches of DNA

Nucleosomes- beads of DNA wrapped around histone

Chromosome- network of DNA coils and proteins

In nucleus

Chromatin- strands of chromosomes, RNA, and proteins

Condensed chromosome- most compact version of DNA

Humans: 46 chromosomes horse: 64, crayfish: 200

Page 27: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Mitosis and InterphaseMitosis- a process of asexual

reproduction in eukaryotic cells

Interphase- time interval between cellular reproduction

Chromosomes not condensed

Cell spends most of its time in this stage

DNA remains in its chromatin form, except when making proteins

Cell cycle- cycle between interphase and mitosis

Page 28: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Mitosis

-In order to reproduce, chromosomes must duplicate

-Sister chromatids- duplicate chromosomes

-The centrioles also duplicate, then mitosis starts

Page 29: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

1. Prophase

-duplicated chromosomes coil into their condensed form

Centromere- the region that joins two sister chromatids

-aster- microtubules extended from centrioles

-as centrioles migrate, the microtubules grow, producing spindle fibers

- Spindle fibers make up the mitotic spindle

Page 30: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

2. Metaphase

-chromosomes are lined up along equatorial plane

Page 31: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

2. Metaphase

-chromosomes are lined up along equatorial plane

3. Anaphase

-microtubules separate the sister chromatids from each other

-sister chromatids are pulled to opposite sides

Page 32: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

2. Metaphase

-chromosomes are lined up along equatorial plane

3. Anaphase

-microtubules separate the sister chromatids from each other

-sister chromatids are pulled to opposite sides

4. Telophase

-spindle begins to disintergrate

-plasma membrane begins to constrict along equatorial plane

Page 33: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

4. Telophase

-spindle begins to disintergrate

-plasma membrane begins to constrict along equatorial plane

-two cells begin to form

-nuclear membrane forms around each chromosome

- chromosomes uncoil from their condensed form back into chromatin

-the end result is two identical daughter cells

Page 34: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

More About Mitosis

•Each daughter cell gets at least one of each organelle

•If the two cells have only one organelle between them, the organelle is split

•DNA can build up or make new organelles as needed

•The mitochondria has its own DNA so it can replicate itself

Page 35: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

More About Mitosis

•Each daughter cell gets at least one of each organelle

•If the two cells have only one organelle between them, the organelle is split

•DNA can build up or make new organelles as needed

•The mitochondria has its own DNA so it can replicate itself

•Mitosis is a form of asexual reproduction

•Every eukaryotic organism performs mitosis

•Mitosis produces new cells as the organism grows, and replaces dead cells

•Millions of red blood cells die every minute

Page 36: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

More About Mitosis

• Plant mitosis: due to cell wall, the plasma membrane can’t constrict

• Cellulose is formed in the middle, producing the cell well

• Also no centrioles are in the plant cells

Page 37: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

ChromosomesKaryotype- the figure produced when chromosomes of a species during metaphase are arranged according to their homologous pairs

-Homologous pairs- chromosomes that are very similar but not identical

-Sex chromosomes- a pair of chromosomes which can be used to

distinguish between the sexes- XX: female

- XY: male

Page 38: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Diploid and Haploid Cells

•each homologue has exactly the same number of genes as its partner

•For example, the gene for blood type can be found on chromosome #9- on one homologue, the gene might be for blood type A and on the other, O.

•Diploid cell- a cell with chromosomes that come in homologous pairs

•Haploid cell- a cell that has only one representative of each pair

Page 39: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Diploid and Haploid Cells•Even species that have diploid cells will have some haploid cells

•Diploid number (2n)- total number of chromosomes in a diploid cell

•46 for human

•Haploid number- (n) number of homologous pairs in a diploid cell

•23 for human

Page 40: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Sexual Reproduction

Meiosis – the process by which a diploid (2n) cell forms gametes (n)

-each parent contributes 23 chromosomes

-In meiosis, diploid cells get split into haploid cells called gametes

-Gametes- haploid cells produced by diploid cells for purpose of sexual reproduction

-Female: egg (ovum) Male: sperm

-Two gametes join together to form a|diploid cell that has 23 homologous pairs of chromosomes- zygote

Page 41: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Meiosis IMeiosis I- one diploid cell forms two

haploid cells

-two begin meiosis, cell must duplicate DNA and centrioles

- Prophase I- centrioles move to opposite sides of cell

- DNA is exchanged between homologous chromosomes (cross over)

- Mitotic spindle forms

- Metaphase I- single microtubule for each pair- chromatids stay intact

Page 42: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Meiosis I

Anaphase I- homologous pairs are pulled to either side

Telophase I- plasma membrane constricts along equatorial plane

-two haploid cells are formed

-though each cell has 46 chromosomes, the cells are considered haploid because the chromosomes are paired with an exact duplicate, leaving 23 unique chromosomes

Page 43: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Meiosis Prophase II- both cells have their centrioles duplicate and form a spindle

Metaphase II- chromosomes line up along equatorial plane

-chromosomes attach to each chromatid

Anaphase II- the microtubules pull the chromosomes away fromtheir duplicates

Telophase II- plasma membrane constricts along equatorial plane, forming two pairs of haploid cells

Page 44: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Mitosis vs. Meiosis

Mitosis: one diploid cell forms two duplicate diploid cells

Meiosis: diploid to haploid

-One diploid cell forms 4 haploid cells

Page 45: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Spermatogenesis

-In males, meiosis produces sperm cells

- At the end of meiosis II, flagella emerges on each of the four haploid cells

Page 46: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Oogenesis

Oogenesis: meiosis in females

-at the end of telophase I, one of the two cells produced takes most of the cytoplasm and organelles

-After meiosis II, one of the big cells from Meiosis I takes most of the cytoplasm and organelles

-the end result is one large gamete (Egg cell) and three smaller polar bodies

- when the sperm burrows into the egg, it forms a diploid cell called a zygote

Page 47: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Viruses

Virus- non-cellular infectious agent

1. has genetic material (RNA or DNA) inside a protective protein coat

2. cannot reproduce on its own

-a virus hijacks a cell in order to reproduce

-because a virus cannot reproduce on its own, it’s not alive

Page 48: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Lytic Pathway

1. Virus attaches to bacterium

2. Virus injects own genetic material

3. Virus DNA instructs bacteria to make viral proteins and genetic material

4. Viruses form in cell

5. Cell ruptures, releasing several viruses

Page 49: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Viruses

•Some viruses, like HIV, can inject genes into the cell and lie dormant for several years before the lytic pathway starts

•Viruses: chicken pox, flu, mumps, cold, mumps, measles, AIDS, cold sores, some forms of cancer

•Viruses affect plants, animals, and bacteria

Page 50: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

The Immune System

Phagocytic cells- purpose is to engulf and destroy pathogens (eg. White blood cells)

Lymph nodes- a place for phagocytic cells to gather

-lymph carries pathogens through the lymph nodes, where the phagocytic cells destroy them

Antibodies- specialized proteins that aid in destroying infectious agents

Page 51: Cellular Reproduction and DNA Offspring receive their traits from their parents- but sometimes the child looks nothing like the parents.

Antibodies-some antibodies can destroy many

kinds of pathogens, others can only fight one kind

-when the body is infected, it produces antibodies that will destroy the pathogen

-the body remembers which antibodies will fight a particular disease

Vaccine- a weakened or inactive version of a pathogen that stimulates the body’s production of antibodies which can aid in destroying a pathogen


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