Genetics

Question 1

what is the Central Dogma

Answer 1

DNA is transcribed to RNA, which is translated into amino acids to form a protein

Question 2

what is epigenetics

Answer 2

a term used to describe changes that are made around the genome that do not alter the actual nucleotide

Question 3

do histones give proteins a net positive or negative charge at the normal pH of the cell

Answer 3

positive

Question 4

true or false - in animals, DNA is only found in the nucleus

Answer 4

false - it is also found in the mitochondria

Question 5

what is the difference between euchromatin and heterochromatin

Answer 5

euchromatin is accessible to the cell’s translation machinery and only coiled during nuclear division
heterochromatin is not accessible to cellular machinery and will not be transcribed

Question 6

what is the most common example of epigenetic regulation

Answer 6

DNA methylation

Question 7

what is DNA methylation

Answer 7

involves the addition of an extra methyl to cytosine nucleotides and it causes DNA to be coiled more tightly

Question 8

what is polyploidy

Answer 8

occurs when a cell has more than two copies of homologous chromosomes`

Question 9

what happens during the initiation step of transcription

Answer 9

a group of DNA binding proteins (TFs) binds to the promoter on the DNA strand

Question 10

what is the major enzyme of transcription

Answer 10

RNA polymerase

Question 11

in what direction does RNA polymerase move along the DNA and what is the direction of the new RNA strand being made

Answer 11

3’->5’ and 5’->3’

Question 12

how are activators and repressors regulated

Answer 12

they are allosterically regulated by cAMP

Question 13

what is an operon

Answer 13

a genetic unit composed of a promoter, operator and genes

Question 14

what are the 2 conditions needed to activate the lac operon

Answer 14

1. lack of glucose

2. lactose is present

Question 15

what is gene repression

Answer 15

when there is no lactose, the lac repressor protein binds to the operator site and prevents the transcription of lac genes

Question 16

what are release factors

Answer 16

trigger termination of translation

Question 17

true or false - proteins translated by free floating ribosomes function in the cytosol

Answer 17

true

Question 18

what is the difference between a promoter and a primer

Answer 18

a promoter is a spot on the DNA that signals the RNA polymerase where to begin transcriptipn
a primer is a short piece of RNA that starts replication

Question 19

what are the steps of mitosis

Answer 19

prophase, metaphase, anaphase, cytokinesis, telophase

Question 20

what is involved in prophase of mitosis

Answer 20

sister chromatids are joined at centromeres; the centrioles move to opposite sides of the cell; the nuclear envelope disappears; the spindle forms and the kinetechore microtubules grow from the spindle and connect the centrioles

Question 21

what is involved in metaphase of mitosis

Answer 21

chromosomes align along the middle of the cell on the microtubules

Question 22

what is involved in anaphase of mitosis

Answer 22

the sister chromatids split from the centromeres and move to the opposite sides of the cell

Question 23

what is involved in cytokinesis

Answer 23

the actual separation of the cellular cytoplasm

Question 24

what is involved in telophase

Answer 24

decondensation of the chromosomes and the nuclear membranes reform

Question 25

what is the result of mitosis

Answer 25

two identical daughter cells with each containing one complete copy of the parent's genomes

Question 26

what are point mutations

Answer 26

a mutation that changes a single nucleotide in a DNA

Question 27

what is a transition mutation

Answer 27

a base substitution exchanging a purine to a purine or pyrimidine to pyrimidine

Question 28

what is a transversion mutation

Answer 28

a base substitution exchanging a pyrimidine to a purine

Question 29

what are the two types of point mutations

Answer 29

addition and deletion

Question 30

what are the four mutations at the level of a chromosome

Answer 30

deletion, duplication, inversion and translocation

Question 31

what is the difference between proto-oncogenes and oncogenes

Answer 31

proto-oncogenes stimulate normal growth in human cells whereas oncogenes cause cancer

Question 32

what are the steps of meiosis

Answer 32

prophase 1, metaphase 1, anaphase 1, telophase 1 | prophase 2, metaphase 2, anaphase 2, telophase 2

Question 33

what is involved in meiosis 1

Answer 33

prophase 1 - homologous chromosomes line up beside each other to match their genes metaphase 1 - the two homologous chromosomes remain attached and move to the metaphase plate anaphase 1 - the pairs of homologous chromosomes separate to create haploid cells telophase 1 - cytokinesis occurs and produces two daughter cells

Question 34

what is the result of meiosis 2

Answer 34

the end result produces 4 daughter haploid cells

Question 35

what is nondisjunction and when can it occur

Answer 35

this occurs in anaphase 1 or 2. it is when the centromere of a chromosome does not split therefore, one of the cells will have two extra chromatids and one of the cells will be missing one.

Question 36

when does crossing over occur and what does it do

Answer 36

prophase 1 ; the exchange of DNA nucleotides

Question 37

what is the number of chromosomes at the start and finish of replication

Answer 37

``` start = 46 chromosomes finish = 46 chromosomes, 92 chromatids (diploid with sisters) ```

Question 38

what is the number of chromosomes at the start and finish of mitosis

Answer 38

``` start = diploid with sisters ; 46 chromosomes , 92 chromatids finish = 46 chromosomes ```

Question 39

what is the number of chromosomes at the start and finish of meiosis 1

Answer 39

``` start = diploid with sisters ; 46 chromosomes , 92 chromatids finish = haploid with sisters ; 46 chromosomes , 92 chromatids ```

Question 40

what is the number of chromosomes at the start and finish of meiosis 2

Answer 40

``` start = haploid with sisters ; 46 chromosomes, 92 chromatids finish = haploid ; 23 chromosomes ```

Question 41

what is the mendelian ratio

Answer 41

3:1

Question 42

what is the law of segregation

Answer 42

alleles segregate independently when forming gametes during meiosis

Question 43

what is the law of independent assortment

Answer 43

genes located on separate chromosomes assort independently; i.e when genes code for different traits, on separate chromosomes, they do not affect each other

Question 44

what is the equation that predicts the genotype frequencies of a gene with only two alleles in the Hardy Weinberg population

Answer 44

p^2 + q^2 + 2pq = 1