B3 GENETICS

Question 1

gametes

Answer 1

egg and sperm cell

Question 2

fertilisation

Answer 2

sperm cell fuses with egg cell and nuclei combine

Question 3

zygote

Answer 3

single cell formed by fertilisation

Question 4

gene

Answer 4

length of DNA coding for a protein

controls your characteristics

Question 5

genome

Answer 5

all the DNA and genes in an organism

Question 6

protein

Answer 6

polymer made from amino acids

Question 7

polymer

Answer 7

long molecule made by chaining together many shorter ones

Question 8

diploid

Answer 8

a cell with 23 pairs of chromosomes (46 in total)

Question 9

haploid

Answer 9

a cell with 23 single chromosomes

Question 10

meiosis

Answer 10

cell division that makes gametes

Question 11

meiosis stages

Answer 11

DNA replicates cell divides into 2 diploid cells, these divide into 4 haploid daughters

Question 12

why gametes are different

Answer 12

chromosomes in a pair are slightly different. Different gametes get different combinations of chromosomes

Question 13

Chromosome

Answer 13

large DNA molecule made into a small package by tightly coiling DNA around a protein

Question 14

DNA structure

Answer 14

two strands , double helix , complementary base pairs , sugar-phosphate backbone

Question 15

DNA bases

Answer 15

adenine A thymine T

cystosine C guanine G

Question 16

complementary base pairs

Answer 16

A pairs with T

C pairs with G

Question 17

hydrogen bonds

Answer 17

weak force holding the two strands of DNA together

Question 18

DNA analysis

Answer 18

issues small differences in DNA to determine family relationships or link people to crimes

Question 19

Allele

Answer 19

different version of the same gene. we have two alleles of each gene

Question 20

homozygous

Answer 20

we have two copies of the same allele

Question 21

heterozygous

Answer 21

we have two different copies of an allele

Question 22

dominant allele

Answer 22

one copy needed for characteristics to show. written as a capital

Question 23

recessive allele

Answer 23

two copies for the characteristics to show. written as lowercase

Question 24

genotype

Answer 24

the combination of alleles in an organism

Question 25

phenotype

Answer 25

the characteristics produced by the alleles

Question 26

genetic diagram

Answer 26

shows the likelihood of offspring produced by parents with certain genotypes

Question 27

sex chromosomes

Answer 27

female: XX male: XY

Question 28

inheriting sex

Answer 28

all eggs are, X 50% of sperm are X and 50% are Y so 50% of zygotes are XX and 50% are XY

Question 29

punnett squares

Answer 29

uses the genotypes of male and female gametes to predict the predict the genotyping of the offspring

Question 30

probability and punnett squares

Answer 30

punnett squares tell you the likelihood of certain offspring not what will actually happen

Question 31

cystic fibrosis

Answer 31

illness caused by a inheriting two copies of a faulty recessive allele

Question 32

family pedigree chart

Answer 32

chart showing how genotypes are inherited down through a family

Question 33

mutation

Answer 33

a change to the bases in a gene

Question 34

effects of mutation

Answer 34

change the structure of a protein and how it works . sometimes harmless, normally harmful, very rarely beneficial

Question 35

cause of mutations

Answer 35

mistakes copying DNA during cell division, DNA damage from chemicals or radiation

Question 36

inheriting mutations

Answer 36

only if they occur in gametes (egg and sperm)

Question 37

human genome project

Answer 37

project involving many scientists from many countries to find the order of bases in human DNA

Question 38

how is HGP useful

Answer 38

to tailor drugs to genes , to design better drugs

Question 39

genetic differences

Answer 39

HGP found 99% of DNA in all people is identical

Question 40

variation

Answer 40

natural differences between members of a species that affect the chance of survival

Question 41

genetic variation

Answer 41

variation caused by genes

Question 42

environmental variation

Answer 42

caused by interaction with the surroundings such as food, climate etc

Question 43

causes of most variation

Answer 43

a combination of genes and the environment

Question 44

acquired characteristics

Answer 44

changes caused by the environment during your lifetime, such as losing a leg

Question 45

continuous variation

Answer 45

can be anywhere within a range , such as height, following a normal distribution

Question 46

discontinuous variation

Answer 46

can be only one of a few possibilities such as blood type:A,B,AB,O

Question 47

normal distribution

Answer 47

bell heaped curve with more in the middle and fewer either side