Genetics

Question 1

What is DNA?

Answer 1

dioxyribonucleic acid that stores the hereditary information for organisms

Question 2

What is a gene?

Answer 2

segments of DNA that code for a specific peice of information/trait

Question 3

What is the difference between diploid and haploid cells?

Answer 3

Diploid - cells have two copies of each chromosome
(duplicated)
Haploid - cells with one copy of each chromosome (non-duplicated)

Question 4

Define chromosomes and chromotids?

Answer 4

chromosomes - individual coiled up molecules of DNA

chromotids - single arm in the duplicated chromosome

Question 5

What are the three stages in the cell cycle?

Answer 5

inter-phase, mitosis and cytokenesis

Question 6

What happens during inter-phase?

Answer 6

period between cell divisions
cell undergo their normal activities
3 sub-stages are G1 phase, synthesis phase and G2 phase
in s phase DNA is replicated for cell division

Question 7

What is mitosis? How many stages are there?

Answer 7

process of cell division

there are four stages

Question 8

What happens during pro-phase?

Answer 8

chromatin coils to form chromosomes to shorten and thicken

Question 9

What happens during meta-phase?

Answer 9

the micro-tubules line up on the middle of the cell preparing to split

Question 10

What happens during ana-phase?

Answer 10

chromatids separate and move to the outside of the cells pulled by spindles

Question 11

What happens during tele-phase?

Answer 11

reforms to make two nuclei and a wall forms between them

Question 12

What happens in cytokineses?

Answer 12

The cytoplasm and organelles are divided between the daughter cells

Question 13

What are the 8 stages of meiosis?

Answer 13

prophase I, metaphase I, anaphase 1, telephase 1

prohase II, metaphase II, anaphase II, telephase II

Question 14

How many cells are produced by meiosis?

Answer 14

Four

Question 15

What happens in meiosis I and II that is different from mitosis?

Answer 15

In meiosis I, the homologous pairs are pulled are part while the sister chromatids stay together

• in meiosis II, the sister chromatids are split
• the number of chromosomes in the daughter cells is 23

Question 16

What is an allele?

Answer 16

• the possible forms of a gene
• some are more dominant over the others
  ex. brown hair and blonde hair

Question 17

Define genotype

Answer 17

the genetic makeup of an individual

ex. BB, Bb, bb

Question 18

Define phenotype

Answer 18

the physical appearance of an individual

ex. brown or blue eyes

Question 19

who was Gregor Mendel and what did he contribute to biology?

Answer 19

-First person to look at dominance, segregation and independent assortment

Question 20

How many traits do dihybrid crosses look at?

Answer 20

2

Question 21

define incomplete dominance

Answer 21

• where neither trait is dominant so they both inluence the final colour, creating a blend
  ex. white + yellow guinea pig = cream babies

Question 22

define codominance

Answer 22

• neither trait is dominant so both alleles are expressed fully
  ex. black + white cat = black and white cat

Question 23

What forms of dominance do blood types have?

Answer 23

dominant/recessive (Iai) and incomplete (IaIb)

Question 24

What is a pedigree?

Answer 24

a chart of genetic relationships based on several generation that shows certain traits, used instead of test crosses, helps determine the dominance of the allele