Exam 2 Review

What is nondisjunction, and during which phases of Meiosis can it occur?

- In nondisjunction, the members of a chromosome pair fail to separate at anaphase, which produces gametes with an incorrect number of chromosomes. - It can occur during meiosis I or II.

which of the following refers to a situation when one gene has effects on multiple traits?

Pleiotrophy

Which is the most common cancer in American women?

Breast cancer

During Metaphase, the chromosomes are pulled towards opposite poles of the cell. T/F?

False

Proto-oncogenes are "accelerators". True or False

False

sex linked traits are more common in females, T/F?

False

a homozygous dominant red cow (RR) and a homozygous recessive white cow (rr) are crossed. genotypic ratio? phenotypic ratio?

GR: 100% Rr PR: 100% red

Diabetes type 2 increases the risk of liver, endometrial and pancreatic cancer. T/F

True

Sister chromatids are matching pairs of chromosomes that can possess different versions of the same gene. T/F?

True

Turner's Syndrome occurs when non-disjunction causes ?

an individual to only have one X chromosome (X0)

When do daughter chromosomes separate in mitosis?

anaphase

Normal cells typically can only divide a finite number of times before they die. However, cancer cells do not have the ability to initiate death via _____________ and may divide indefinitely.

apoptosis

sex influenced traits are:

autosomal traits that are expressed differently in males and females

Comparison of a cancer cell and a normal cell reveals that

cancer cells do not undergo contact inhibition, normal cells do

Which of the following are NOT found in genetically normal cells

cell division beyond the Hayflick limit

What is the main event that helps create genetic diversity in meiosis?

crossing over

Meiosis results in the production of _________ daughter cells, called _________

four; diploids

Which of the following is not a risk factor for breast cancer?

high fiber diet

Explain in 1-2 sentences why human height is a polygenic trait. Provide 1 example of polygenic traits in humans

in polygenic inheritance, traits are determined by multiple genes. human height - controlled by at least 3 genes with 6 alleles

the abnormal gene responsible for hemophilia is carried on the X chromosome. men are more likely to have this disease because:

women have two X chromosomes, and need to inherit hemophilia on each to present the disease

Which phase of the cell cycle does MPF levels (Maturation Promoting Factors) trigger?

M

What is necrosis, and why can it be damaging to surrounding cells?

- Necrosis is a form of cell death that has low oxygen, toxins, ATP depletion, and random fragmentation. It is ingested by phagocytes. - It causes inflammation and can be damaging to surrounding cells because there are microbial substances that are released by the leukocytes which has great potential to seriously harm nearby cells.

Define oncogene and tumor suppressor gene and state the relationship between the two.

- oncogene: accelerator mutated genes that promote abnormally high levels of cell growth that cause cancer - tumor suppressor gene: brake genes that prevent uncontrolled cell growth and when mutated, can contribute to cancer - relationship btw the two: mutations are a product of the formation of oncogenes and the destruction of tumor suppressor genes

Define a tumor suppressor gene. Provide one example of a common tumor suppressor gene.

- prevents uncontrolled cell growth (brakes) - when mutated --> contribute to cancer - ex. PTEN

What is the correct sequence of the phases in Mitosis?

- prophase - metaphase - anaphase - telophase - cytokinesis

What are TWO regulatory characteristics that normal cells have when they are growing and diving that cancer cells do not have?

1) Anchorage dependence, which means that in order to divide, they must be attached to a substratum. 2) Density-dependent inhibition (contact inhibition), which checks the growth of cells at an optimal density.

Imagine you notice a "mole" on the surface of your face. Name two characteristics that lead you to think that you may have skin cancer (melanoma).

1) asymmetry (one half doesn't match the other) 2) border irregularity

a homozygous green pea (GG) and a homozygous yellow pea (gg) cross pollinate and the offspring are green. what is/are the genotype(s) of the offspring?

100% Gg

What nondisjunction disease is caused by trisomy in chromosome 18?

Edwards Syndrome

Which month is the Breast Cancer Awareness Month in the US?

None of these (October)

Crossing over (the trading of genetic material between non-sister chromatids during meiosis) occurs during which phase of meiosis?

Prophase I

At what stage does DNA replicate?

S phase

When does a cell become cancerous? When

a cell starts making too many proteins that trigger a cell to divide

Proto-oncogenes are:

normal genes

which of the following are autosomal lethal recessive?

sickle cell anemia and PKU