section 3

Question 1

chromosome:

Answer 1

large package of coiled DNA; all species have different numbers
→ humans have 46 – one from each parent

Question 2

DNA

Answer 2

codes for information that makes an organism

[large molecule shaped as a double helix]

Question 3

two types of DNA base

Answer 3

A - T
C - G

adenine - thymine
cystosine - guanine

Question 4

gene

Answer 4

section of DNA that codes for a certain trait/instruction

genes come in pairs

ex. the gene for eye colour is found on chromosome 15

Question 5

allele

Answer 5

different forms of a gene

ex. different allele for eye colour

Question 6

how is cell division different from organisms that reproduce asexually and sexually?

Answer 6

asexual: for reproduction [identical offspring]
sexual: for growth and repair

Question 7

cell division

mitosis

any ways to remember?

Answer 7

cell division that results in two cells with the same number of chromosomes [identical]
occurs in the body cells

my toe sis – toe is a body part [body cells]
miTosis – T for two

Question 8

cell division

meiosis

ways to remember?

Answer 8

results in gametes with half the number of chromosomes
when the gametes unite the zygote will have necessary chromosomes to make a unique individual

occurs in sex cells [gametes]

Question 9

dominant gene:

Answer 9

overpowers recessive genes

→ represented by a capital letter [A, B, H, X]

Question 10

recessive gene:

Answer 10

two recessive genes needed for recessive trait to be expressed

→ represented by a lowercase letter [a, b, h, x]

Question 11

purebred

other name?

Answer 11

ancestors have produced only one type
of offspring for several generations

HOMOZYGOUS

HH or hh

Question 12

hybrid

other name?

Answer 12

one dominant and one recessive allele for a given trait

HETEROZYGOUS

Hh

Question 13

genotype

Answer 13

genetic coding an organism has

G - genetic

ex. Hh, HH, hh

Question 14

phenotype

Answer 14

physical representation of the genotype

PH - physical or photo

ex. pink flower or red flower

Question 15

what are the two patterns of inheritance

Answer 15

1) dominant/recessive
2) incomplete dominance

Question 16

patterns of inheritance

1) dominant/recessive

Answer 16

some alleles will be dominant
→ if a dominant is present it will be expressed
some alleles will be recessive
→ will only be expressed if no dominant allele is present

if R = red flower [D], r = pink flower [R]
Rr = red, RR = red, rr = pink

Question 17

patterns of inheritance

2) incomplete dominance

Answer 17

neither allele is dominant or recessive [dominance is shared]
→ hybrid will show a mix of the trait

when a purebred red flower is crossed with a purebred white flower, the resulting flowers are pink
red flower x white flower = pink flower