BIOL 1710 Exam #3 Review

Mitosis

100

What stage of mitosis are the chromosomes split apart?

Anaphase

200

What is the order of the phases of mitosis?

PPMAT

Prophase, Prometaphase, Metaphase, Anaphase, Telophase, Cytokinesis

300

What does mitosis produce?

2 genetically identical daughter cells

400

What type of cells can mitosis happen in?

somatic

500

How many chromosomes do we have as humans, and are these haploid or diploid?

46 chromosomes (23 pairs), Diploid

Meiosis

100

What are the stages of Meiosis?

PMATPMAT

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

200

Meiosis produces...

4 genetically different daughter cells (Gametes)

300

What is the difference between Anaphase I and II?

Anaphase I has the homologous chromosomes split into their own individual chromosome pairs, Anaphase II has the sister chromosomes split into their own individual chromosomes.

400

What would happen if nondisjunction was present in anaphase II?

The chromosomes won't split properly which will lead to one too many or one too little chromosomes. If present in human's chromosome 21, one too many will cause down syndrome. Usually lethal in other cases.

500

Are the gametes going to re-undergo meiosis after they have been formed like the daughter cells in mitosis?

No, the gametes are intended to be expelled from the body. (Ex. A Female's Period)

Genetics

100

What is an Allele?

One copy of a gene, can be dominant or recessive.

200

What is the difference between phenotype and genotype?

Phenotype - What you see

Genotype - Whats in your genes/DNA

300

What is the place in which a gene is located on a chromosome called?

a locus

400

What are the three types of dominance?

Complete Dominance, Codominance, Incomplete Dominance

500

If a red flower mates with a white flower and their offspring is pink, what type of dominance is present?

Incomplete Dominance - Neither are independently present, however they are both present mixed.

Punnett Squares

100

Perform a cross between AA and aa

Aa  Aa

Aa  Aa

200

Perform a cross between XY and X^CX

X^CX  XX

X^CY  XY

300

If the offspring look like

X^SY  XY

X^SX  XX

What percentage of the offspring have the X^S gene Phenotype?

25% -> X^SY only

400

If the offspring look like

BB  Bb

Bb  bb

What are the genotypes of the parents?

Bb, Bb

500

If the offspring of a XY and X^RX cross display a 33.3% carrier and a 66.6% healthy ratio, what can be assumed about the X^R gene?

The cross would look like

X^RX  XX

X^RY  XY

So in order for the percentages to show thirds, the X^R gene is lethal, and the son affected would die.

Misc.

100

What is the metaphase plate?

An imaginary line (similar to the equator) in which the chromosome pairs line up on

200

What happens in the G₀ phase of interphase?

Nothing in particular, the cell just carries out its own functions.

300

Why is genetic diversity needed?

So that species can survive in changing environments

400

What type of dominance is displayed if black and white cows mate and get a black and white spotted offspring?

Codominance - Both phenotypes are present

500

What is the difference between the G₁ and G₂ phases in interphase?

G₁ Has NOT replicated and cell continues normal cell function, just growing.

G₂ HAS replicated DNA, and most of the cell's energy is used copying organelles and everything needed for the split.