Genetics

Question 1

What are sections divided into

Answer 1

genes

Question 2

what do genes carry

Answer 2

all the genetic information needed by the cell to make one particular protein

Question 3

what is dna made of

Answer 3

nucleiotides

Question 4

How are the two strands of DNA held together

Answer 4

4 bases attached to each sugar (A,C,T or G).
Attractions between bases are called hydrogen bonds.The pairs of bases are complementary base pairs.They hold the strands of a DNA molecule together.

Question 5

homozygous

Answer 5

having 2 identical alleles for a particular characteristic

Question 5

what are the 3 parts that make up a nucleiotide

Answer 5

phosphate group,deoxyribose sugar,nitrogen base

Question 6

dominant

Answer 6

an allele that has an effect in both heterozygous and homozygous conditions

Question 7

genotype

Answer 7

the genes/alleles that an organism possesses

Question 8

recessive

Answer 8

an allele that only has an effect in the homozygous condition

Question 9

phenotype

Answer 9

an organisms outward appearance/characteristics

Question 10

heterozygous

Answer 10

having 2 different alleles for a particular characteristic

Question 11

alleles

Answer 11

different forms of the same gene

Question 12

homologous pairs

Answer 12

pair of chromosomes with the same genes of the same loci

Question 13

expressed

Answer 13

when the gene to produce a certain protein is turned on

Question 14

pure-breeding

Answer 14

organisms which always produce identical offspring generation after generation as they are homozygous

Question 15

test cross

Answer 15

when u breed an animal with a homozygous recessive to work out the genotype

Question 16

name some examples of recessive diseases

Answer 16

cystic fibrosis, sickle cell anemia

Question 17

how do u suffer from recessive diseases

Answer 17

you have to have 2 copies of the recessive allele

Question 18

give some examples of dominant conditions

Answer 18

polydactyl ,Huntingtons

Question 19

are there carriers of dominant conditions?

Answer 19

no because if you have the allele it will be expressed

Question 20

How is gender determined

Answer 20

each human body cell has 22 pairs of chromosomes and one other pair, this pair is the sex chromosome
female cells have 2 similar chromosomes- XX
male cells have 2 different chromosomes- XY

Question 21

what is polygenic inheritance

Answer 21

when human characteristics are controlled by many genes not just one

Question 22

what is a mutation

Answer 22

a change in a gene that creates a new allele is called a mutation

Question 23

when is do mutations occur the most

Answer 23

common during cell division because that is when DNA is copied and errors can be made

Question 24

what is codominance

Answer 24

when both alleles in a gene are expressed in a phenotype

Question 25

what is the chart from blood in humans for codominance

Answer 25

-Alleles IA and IB are codominant, but both are dominant to IO -IA results in the production of antigen A in the blood -IB results in the production of antigen B in the blood -IO results in no antigens being produced in the blood

Question 26

how to extract dna from fruit

Answer 26

-pour salt solution into beaker and add washing up liquid and stir until dissolving. -mash up fruit,add to beaker and stir -transfer contents to boiling tube -place in water bath for 15minutes -use filter to drain out physical bits -add 2 drops of enzyme solution to filtrate and swirl -tilt tube slightly and add ice cold ethanol -after a few minutes there should be a white layer between juice + ethanol, this is dna

Question 27

why are enzymes used to extract the DNA

Answer 27

chromosomes in the plant cells also contain protein, enzyme helps to break them down

Question 28

what are the steps of meiosis

Answer 28

interphase,prophase 1 ,metaphase 1 , anaphase 1,cytokinesis,metaphase 2,anaphase1,cytokinesis 2

Question 29

what does meiosis produce

Answer 29

4 genetically different haploid daughter cells (gametes)

Question 30

meiosis(interphase)

Answer 30

the cell replicates the dna

Question 31

meiosis(anaphase1)

Answer 31

sections of DNA chromosomes are swapped between the maternal and paternal chromosome pairs making recombinant chromosomes

Question 31

meiosis(prophase1)

Answer 31

the nuclear membrane breaks down

Question 32

meiosis(metaphase1)

Answer 32

the maternal and paternal chromosomes pair along the centre of the cell