Unit 1 - Cell division

Question 1

Define Genetics

Answer 1

The Study of heridity and the variation of inherited traits

Question 1

Name and define the 3 subdivisions of genetics

Answer 1

*Tranmission (mandeliean) Genetics: studies of the tranmission of traits to sucessive generations

*Evolutionary genetics : studies the origins and genetic relationships of organisms, and the evolution of genes/ genomes

*Molecular genetics: studies the inheritance and variation of Neuclaic acids, Protiens, and genomes

Question 2

Outline the importance of timing within the cell cycle

Answer 2

The importance of the cell cycle is to control the rate at which cells divide. This ensures that each cell undergoes all the correct processes by passing checkpoints. An example of its importance is cancer, where a cell divides uncontrollably.

Question 3

describe the cell cycle (4)

Answer 3

Interphase:
*G1: gap 1has active gene expression and cell activity

*S: the synthesis phase is when DNA is replicated, and chromosomes are duplicated

*G2: Preperation for cell division

*M: Mitosis (somatic cells) or meiosis (germ-line cells). Results in Karyokenesis, the seperation of DNA into two daughter neucli, and cytokenesis, the seperation of cytoplasm to from 2 daughter cells

Question 4

What are the 5 stages of Mitosis

Answer 4

1. Prophase -> Chromosome condensation begins, resulting in 2 sister chromatids making up each chromosome. Centrosomes migrate to polls and extend microtubles to from early mitotic spindle
2. Prometaphase -> Nuclear envelope disolves, Microtubles bind to kinetochores of chromosome centromeres. Chromosomes are pulled to center of cell
3. metaphase -> Chromosome condensation is complete. Chromosomes are aligned in the center of the cell. mitotic spindle is complete
4. Anaphase -> Sister Chromatids seperate (disjunction) and daughter chromasome are pulled toward opposite polls. Cell is egg shaped
5. Telophase / cytokenesis -> Nuclear envilope begins to reform as cells are pulled further towards polls. Cytokenesis occurs to seperate the two daughter cells

Question 5

Draw Mitosis

Answer 5

find image on google

Question 6

Draw Meiosis I

Answer 6

find image on google

Question 7

Draw Meiosis II

Answer 7

Find Image on google

Question 8

Define Diploid

Answer 8

Having two copies of each chromosome called Homologous pairs (2n = number of chromosomes)

Question 9

Define Haploidtwo

Answer 9

Having only 1 copy of each chromosome (n = number of chromosomes)

Question 10

Define Homologous Chromosome

Answer 10

A chromosome pair found in diploid cells. Each have the same genes in the same order, however small varation between the two can result in them having different alleles.

Question 11

Define sister chromatid

Answer 11

Identical copies formed in DNA replication. Joined at center by centromere.

Question 12

Sister Chromatid vs Homologous Chromosome

Answer 12

*Sister Chromatids are genetically identical and bound togeather forming an “X” shape

*Homologous chromosomes are a NON-IDENTICAL pair of “I” shaped chromosomes NOT bound togeather, they just vibe next to eachother.

Question 13

Define recombination

Answer 13

Process in which peices of DNA are broken and recombined resulting in genetic variation due to crossing over and independent assortment

Question 14

Define Independent assortment

Answer 14

After crossing over, chromosomes in meiosis indpendantly assort themselves so that when the seperate, the resulting gamete is randomized.

Question 15

Define crossing over

Answer 15

Exchange of genetic material in meiosis between a homolgous pair of chromosomes (one from mom and one from dad)

Question 16

Define A Germ cell

Answer 16

Cells in the body that develop into sperm or eggs, haploid

Question 17

Define a somatic cell

Answer 17

non-reporductive cells used for growth, repair, and structure! Diploid

Question 18

Define Telomere

Answer 18

a region of repetitive DNA sequences at the end of a chromosome. Telomeres protect the ends of chromosomes from becoming frayed or tangled, but shorten with each replication

Question 19

Define disjunction

Answer 19

The normal seperation of sister chromatids during anaphase of mitosis and meiosis

Question 20

Define non-disjunction

Answer 20

Nondisjunction is the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes.

Question 21

define Aneuploidy

Answer 21

the presence of an abnormal number of chromosomes in a cell