Genetics

Question 1

ploidy level

Answer 1

the number of chromosome sets that a cell carries Eg haploid 23, diploid 46

Question 2

homogametic sex

Answer 2

individuals with two of the same sex chromosomes

Question 3

heterogametic sex

Answer 3

individuals with two different sex chromosomes

Question 4

somatic cells

Answer 4

all cells in the body of an organism apart form the sex cells (gametes)

Question 5

germ cells

Answer 5

cells that give rise to gametes

Question 6

meiosis type of division

Answer 6

reduction division (number of chromosomes becomes halved)

Question 7

synapsis

Answer 7

when the maternal and paternal homologous pairs of chromosomes pair up

Question 8

chiasma (chiasmata)

Answer 8

the point on the chromosome where crossing over occurs (the chromosome breaks)

Question 9

recombinant chromatids/chromosomes

Answer 9

chromatids that have had crossing over occur to them (they have a new combination of alleles)

Question 10

non-recombinant chromatids/chromosomes

Answer 10

chromatids that have not had crossing over occur to them 9have had no change in their alleles)

Question 11

formula for number of possible chromosome pairs from independent assortment

Answer 11

2^n where n=the haploid number of the organism

Question 12

when are chromosomes most visible

Answer 12

at metaphase

Question 13

genotype

Answer 13

the set of alleles present in the DNA of an individual organism

Question 14

homozygote

Answer 14

an individual with the homozygous genotype

Question 15

heterozygote

Answer 15

an individual with the heterozygous genotype

Question 16

Hemizygous

Answer 16

used to refer to males when talking about X-linked genes. Can be hemizygous dominant/recessive

Question 17

phenotype

Answer 17

the physical representation of the genotype of an individual

Question 18

complete dominance

Answer 18

where one allele is dominant over the other so the heterozygous individuals express the dominant trait only

Question 19

incomplete dominance

Answer 19

when neither allele is dominant over the other so an intermediary or blended phenotype occurs in heterozygous individuals

Question 20

codominance

Answer 20

when both alleles are equally expressed in the heterozygous individual therefore no phenotype of fully dominant

Question 21

epigenetics

Answer 21

different environment causes methyl groups to attach to the cytosine bases of the DNA, however the DNA remains unchanged

Question 22

environmental influencers

Answer 22

DNA is unchanged but the environment changes the way these genes are expressed Eg chemically

Question 23

reprogramming

Answer 23

when epigenetic markers are erased during meiosis

Question 24

genetic cross

Answer 24

the deliberate mating of two organisms to determine the inheritance pattern of particular traits

Question 25

monohybrid cross

Answer 25

a cross following one trait in an organism (same gene at the same locus)

Question 26

dihybrid cross

Answer 26

tracking two traits in an organism (tow different genes at two respective loci)

Question 27

non-linked traits

Answer 27

traits that are inherited independently of one another as they are on separate chromosomes

Question 28

linked genes

Answer 28

genes that are inherited together as they are found on the same chromosome, known as linkage.

Question 29

HhKk + HhKk expected ration

Answer 29

9:3:3:1

Question 30

HhKk + hhkk expected ratio

Answer 30

1:1:1:1

Question 31

fixation

Answer 31

when an allele dominates a whole population

Question 32

trisomy

Answer 32

when there is an extra copy of a chromosome

Question 33

monosomy

Answer 33

when there is only one copy of a chromosome

Question 34

down syndrome: abnormality

Answer 34

trisomy 21

Question 35

down syndrome: symptoms

Answer 35

intellectual disability developmental delays

Question 36

Klinefelter syndrome: abnormality

Answer 36

two x chromosomes and one y

Question 37

Klinefelter syndrome: symptoms

Answer 37

low testosterone reduced male characteristics

Question 38

Turner syndrome: abnormality

Answer 38

missing an X chromosome, have 1 X chromosome

Question 39

Turner syndrome: Symptoms

Answer 39

short stature infertile

Question 40

triplets/codons

Answer 40

DNA is divided into sets of three nucleotide segments which code for amino acids that when join form a protein

Question 41

aneuploidy

Answer 41

an abnormal haploid number of chromosomes

Question 42

test cross

Answer 42

used to find an unknown genotype by crossing an individual with the dominant phenotype with a homozygous recessive individual. Type of monohybrid cross.

Question 43

histone

Answer 43

proteins that the DNA wraps around

Question 44

genome

Answer 44

all the genetic information in a haploid set of chromosomes this can also be used on a larger scale with reference. For example the genome of the cell or person

Question 45

Nucleosome

Answer 45

8 histones wrapped in DNA

Question 46

chromatin

Answer 46

multiple nucleosomes, which makes up Chromosomes