Chapter 2: Genetics

Question 1

define variant

Answer 1

a particular form of a trait (e.g. blue eyes are a variant of eye colour)

Question 2

what are genes?

Answer 2

units of inheritance

Question 3

what is independent assortment?

Answer 3

the idea that each gene at a single location on a pair of chromosomes is equally likely to be transmitted when gametes form

Question 4

what are gametes?

Answer 4

sex cells - egg and sperm cells

Question 5

what is a chromosome?

Answer 5

a linear body in a cells nucleus that appear during cell division and replicate

Question 6

what are cells?

Answer 6

basic unit of life for all organisms

Question 7

what is a prokaryote?

Answer 7

cells with no nucleus/internal components

Question 8

what is a eukaryote?

Answer 8

cells containing a nucleus / internal components separated by membranes

Question 9

what is a nucleus?

Answer 9

a nucleus contains genetic material (chromosomes)

Question 10

how many chromosomes do humans have?

Answer 10

46 chromosomes / 23 pairs

Question 11

what is MITOSIS?

Answer 11

the division of somatic/body cells - produces 2 exact copies of parent

2n -> 2n + 2n (all with 46 chromosomes)

Question 12

what is MEIOSIS?

Answer 12

division of gamete cells - produces four haploid cells

2n -> n + n + n + n (daughter cells have HALF chromosomes, 23)

Question 13

what forms a zygote?

Answer 13

a zygote is formed after meiosis when two haploid cells (sperm and egg) come together

Question 14

what is a zygote?

Answer 14

a single cell that divides over and over to produce cells that make up a human body

Question 15

what are alleles?

Answer 15

different forms of genes

Question 16

describe homozygous vs heterozygous

Answer 16

homozygous: same alleles (aa or AA)
heterozygous: different alleles (Aa)

Question 17

what is a genotype?

Answer 17

the alleles that are carried by an organism

Question 18

what is a phenotype?

Answer 18

physical/observable characteristics

Question 19

what are the two backbone components of DNA?

Answer 19

sugar and phosphate

Question 20

what are the 4 nucleotide bases?

Answer 20

• adenine and thymine
• cytosine and guanine

Question 21

what happens if there is errors in replication?

Answer 21

there can be mutations

Question 22

what is the role of proteins in the body?

Answer 22

regulate gene expression, structure of cells, regulate immune system, etc.

Question 23

what is the function of a protein determined by?

Answer 23

its shape

Question 24

what do regulatory genes do?

Answer 24

turn genes on and off, regulate how much/what protein is made

Question 25

what is the role of RNA?

Answer 25

to manufacture proteins and help genes function

Question 26

what are the 3 steps of DNA coding?

Answer 26

1. DNA is transcribes into mRNA (messenger RNA)
2. mRNA carries the message to ribosomes
3. mRNA is transcribes into amino acid sequences by tRNA (transfer RNA)

Question 27

what nucleotide base is substituted on mRNA?

Answer 27

thymine becomes uracil

Question 28

when does transcription occur?

Answer 28

when an activator is bound (lactose is present, glucose is not present) and a repressor is unbound

(when a repressor binds: there is no lactose and glucose is present) (a-l) (r-g)