BIO REVIEW EXAM 2

HPV

(Human Papillomavirus) a virus that can cause genital warts, cervical cancer, or be asymptomatic. Abilities: 1. Infect human cells 2. Replicate it's genome 3. Make more virus particles 4. Hides from immune system 5. Bust out of human cells 6. Cause cervical cancer.

If two sets of twins get married and each couple has a child, assuming there are no new mutations or meiotic crossover, what are the chances these two children will be girls?

.5 x .5 = .25 or 25%

Germline Cells

Cells that develop into gametes

Mutagen

Chemical or physical agents in the environment that interact with DNA and may cause a mutation. Examples: UV radiation from sun, X-rays, and smoking.

Nancy Wexler

A geneticist that traveled to Venezuela and helped Huntington's disease patients by helping discover the location of the gene that causes Huntington's disease.

Process of DNA Replication

A parent DNA molecult is separated into 2 strands and then DNA polymerase reads these strands and synthesizes a new DNA strand.

Somatic Cells

Body Cells

Telomeres

NUCLEIC ACIDS; Located at the tip of chromosomes and are made of repeating nucleotides: TTAGGG. They protect the ends of chromosomes from becoming tangled. Each time a chromosome is duplicated, telomeres become shorter and shorter.

Telomerase

PROTEINS; An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells. (Or in easier words) Rebuilds telomeres in some cells by adding more TTAGGG repeats to the ends of chromosomes.

Apoptosis

Programmed cell death.

Stages of Meiosis

Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II

Which of the following statements is scientifically accurate? A. Insulin is a carbohydrate B. The cell membrane is primarily composed of nucleic acids C. Sickle cell anemia is made up of nucleic acids D. RNA polymerase is made of amino acids E. A virus is primarily a collection of lipids and proteins

RNA polymerase is made of amino acids

What kinds of mutations in Proto-oncogenes lead to mutations.

Gain of function mutations

Are recessive alleles always a loss of function ?

Generally a loss of function; airpods analogy. Broken airpod is the recessive one because theres no music.

Hemoglobin

Iron-containing protein in red blood cells that carries oxygen for delivery to cells.

Errors in the synthesis of DNA

1. 1 error per 100,000 bases 2. Human genome= 6 billion DNA bases 3. Therefore, 60,000 errors per cell division HOWEVER After proofreading and repair, 1 error per 10 billion bases = .6 errors per cell division

5 Key ideas about the biology of cancer

1. Cancer is uncontrollable cell division (mitosis) 2. Cancerous cells have accumulated genetic damage through mutations 3. Proto-oncogenes are normal genes that code for normal proteins that promote cell division. 4. Tumor suppressor genes are normal genes that code for normal proteins that inhibit cell division. (apoptosis) 5. At least 2 mutation events (and usually more) in these types of genes are required for a cell to become cancerous.

5 ways or more that HeLa cells are different from normal cells

1. Do not undergo apoptosis because of active telomerase 2. More chromosomes (76-80) 3. Invasive (take over other cells) 4. Immortal 5. Airborne 6. Strong/durable

3 Key ideas of meiosis

1. Law of Segregation: Maternal and paternal copies of chromosomes splitting up and ending up in different gametes 2. Law of Independent Assortment: The alleles of two (or more) different genes get sorted into gametes independently of one another. (punnett square) 3. Random Fertilization: Different eggs and sperm will fertilize (like slot machine analogy). Immense number of genetic possibilities. Possibilities created during independent assortment and crossing over.

5 Key ideas about cancer causing mutations

1. Mitosis occurs in SOMATIC cells and produces 2 identical daughter cells 2. Meiosis occurs in GERMLINE cells and produces 4 different gametes 3. Mutations occur in DNA replication and cell division steps of mitosis and meiosis 4. New mutations can occur in somatic or germline cells 5. Only mutations in germline cells and gametes can be inherited.

5 Key Ideas about Inheritance of Cancer Causing Mutations

1. Mitosis occurs in somatic cells and produces 2 identical daughter cells. 2. Meiosis occurs in germline cells and produces 4 different gametes. 3. Mutations cna occur in somatic cells OR germline cells. 4. New mutations can occur in somatic cells. 5. Only mutations in germine cells and gametes can be inherited.

The top sequence represents the "normal" sequence of the first 27 nucleotides of the coding region of the human gene hGRT1. The bottom sequence is a mutated version of the same gene. Original sequence: ATG GTC AGT CTA CAC CTC ACG TTT CTG... Mutated sequence: ATG GTC AGT CTA ACA CCT CAC GTT TCT G... Which of the following statement(s) about these two sequences is/are accurate? Choose ALL that apply. 1. These are two different alleles of the same gene 2. The hGRT1 gene is located in the same position on the same chromosome in all humans. 3. You could have inherited both of the sequences above from the same parent. 4. These sequences could appear on two different chromosomes. (For example, chromosome 1 and the X chromosome) 5. One person could carry both of these sequences in their genome.

1. These are two different alleles of the same gene. 2. The hGRT1 gene is located in the same position on the same chromosome in all humans. 5. One person could carry both of these sequences in their genome.

Two sets of twins marry. Chances of both children being genetically identical is...

1/2^46

Chances you receive the exact subset of chromosomes you inherited from your biological mother and father.

1/2^46 (1/2 is from gender)

How aflatoxins causes mutations

Aflatoxin DNA adducts bind to G which causes the DNA Polymerase to mispair G with A.

Aflatoxins can cause cancer by damaging the...

DNA

If a mutagen reacts with DNA in a cell to form a single DNA, after two cell divisions, what percentage of the daughter cells are likely to have a DNA mutation? After 3? How many daughter cells will have the DNA adduct after two cell divisions? After 3?

DNA Mutation- After 2: 50% 2/4 After 3: 50% 2/4 DNA adduct- After 2: 25% 1/4 After 3: 12.5% 1/8

Aspergillus

FUNGUS; Grows on nuts and grains in hot and humid environments. PRODUCES AFLATOXIN.

What kinds of mutations in tumor suppressor genes lead to cancer?

Loss of function mutations (LoF)

Stem length from Mendel's Peas experiment.

The enzyme (or protein) 3 beta-hydroxylase activates giberellin (plant hormone). The recessive allele forces a point substitution at amino acid 229. It substituted G to A in the DNA which causes an Ala to be replaced with a Thr. This causes for the enzyme to be nonfunctional and no longer activate giberellin which leads to a short stem length. The reason why a trait is recessive in this situation is because the enzyme is nonfunctional, the mutation in the recessive gene results in a loss of function. A loss of function in the 3 beta-hydroxylase cannot activate giberellin which results in a short stem length.

The HPV E6 gene encodes a protein that binds and inactivates a human protein, contributing to cancer. What are these proteins most likely to be encoded by? Give 2 reasons to support your answer. A. Tumor Suppressor Genes B. Proto-oncogenes

Tumor Suppressor Genes 1. HPV E6 gene binds p53 which is a tumor suppressor gene. 2. Tumor suppressor gene loses function; they can no longer promote programmed cell death which leads to cancer.

U-ABC-IT

Use evidence, ask questions, be skeptical, cultivate wonder, identify confusions, think like a biologist.

haplosufficient

When one functional allele is enough to maintain the normal function of the gene.

Stages of Mitosis

prophase, metaphase, anaphase, telophase (PMAT)