topic B6 - inheritance

Question 1

define chromosome

Answer 1

a structure found in the nucleus which is made up a long strand of DNA

Question 2

define gene

Answer 2

a small section of the DNA which codes a particular sequence of amino acids to form a specific protein

Question 3

DNA

Answer 3

a long thread of genetic material that forms a double helix

Question 4

genome

Answer 4

is the entire genetic material of that organism

Question 5

alleles

Answer 5

different forms of the genes

Question 6

clones

Answer 6

an organism that is genetically identical

Question 7

phenotype

Answer 7

the physical characteristic

Question 8

genotype

Answer 8

genotype is a combination of alleles of an organism inherits from its parents - the genetic makeup of an individual

Question 9

heterozygous

give examples

Answer 9

different alleles are present

Bb

Question 10

homozygous

example

Answer 10

when both alleles are the same
bb
BB

Question 11

gamete

Answer 11

a sex cell with half a set of chromosome of the parent

Question 12

mitosis

Answer 12

one cell is copied into 2 identical cell

Question 13

dominant alleles are represented

example

Answer 13

capital letters

BB

Question 14

if the alleles are dominant

Answer 14

the phenotype is the allele that is dominant

Question 15

recessive allele

Answer 15

are represented by lower case

Question 16

how many copies of recessive alleles

Answer 16

2 copied are needed or no dominant allele

Question 17

cystic fibrosis

Answer 17

is a disorder of the cell membrane resulting in thick mucus in the airways and the pancreas

Question 18

key points of cystic fibrosis

Answer 18

controlled by single gene

caused by a recessive allele

Question 19

in order to have cystic fibrosis

Answer 19

both parents need to either be carriers - have one recessive allele each

or

one parent must have 2 copies of the recessive allele

Question 20

what sort of people won’t have cystic fibrosis

Answer 20

a person with one recessive allele and one normal allele does not have cf but are carriers

Question 21

polydactyly

Answer 21

having an extra finger/toes

Question 22

what causes polydactyly

Answer 22

dominant allele

Question 23

why can’t you be a carrier for polydactyl

Answer 23

because the dominant allele will have that characteristic

Question 24

female gene

Answer 24

XX

Question 25

male gene

Answer 25

XY

Question 26

reproductive organs

Answer 26

testes and ovary

Question 27

what is embryo screening

Answer 27

when embryo is screened / checked for genetic disorders

Question 28

stages of embryo screening

Answer 28

during IVF embryo are fertilised in a laboratory then one cell from each embryo is removed and gene is tested to see if it has the genetic disorder and it is then implanted back into the mothers womb

Question 29

arguments against embryonic screening

Answer 29

embryo screening is very expensive and some may think that money should be spent elsewhere in the healthcare could encourage to pick a desirable characteristic (creating designer baby ) people may find this unethical the procedure can lead to miscarriages may promote prejudice as it suggests that those with genetic disorders will not live a full life or might be discriminated an increase in abortion

Question 30

arguments for embryo screening

Answer 30

maybe able to correct family alleles be able to treat inherited disorders reduce the number of suffering there is a regulation in pace to stop it from getting out of control

Question 31

sexual reproduction

Answer 31

sexual reproduction occurs in meiosis to form 4 non-identical cells called gametes . it involves the fusion of a male and female gamete . the cell divides twice and each gamete - half the set of chromosomes haploid , the genetic information from each parent is mixed , producing a variation in the offspring .for example of sexual reproduction is sperm cell fusing with the egg cell

Question 32

asexual reproduction

Answer 32

asexual reproduction occurs in mitosis so one cell is copied into 2 genetically identical cells. it has a full set of chromosome - diploid and because there is no mixing of of genetic information so the offspring can form clones.

Question 33

asexual reproduction occurs in

Answer 33

mitosis

Question 34

sexual reproduction occurs in

Answer 34

meiosis

Question 35

asexual forms

Answer 35

2 genetically identical cells

Question 36

sexual forms

Answer 36

4 non-identical cells called gametes

Question 37

asexual chromosome

Answer 37

diploid - full set of chromosome

Question 38

sexual reproduction

Answer 38

haploid - half set

Question 39

the offspring of asexual reproduction

Answer 39

genetically identical and can form clones

Question 40

the offspring of sexual reproduction

Answer 40

produces variations in the offspring

Question 41

stages in meiosis

Answer 41

in the first stage of meiosis, the cell makes copies of chromosome the cell divides into 2 - each with half the amount of chromosome 46 then it divides again producing 4 cells - 23 chromosome these cells are called gametes and are all genetically non-identical from each other

Question 42

fertilisation

Answer 42

the male gamete - containing 23 chromosome and the female gamete also containing 23 chromosome fuse at fertilisation to produce a cell with 46 chromosome

Question 43

what happened after fertilisation

Answer 43

the cell divides by mitosis to produce a clump of identical cells more and more cells are produced forming an embryo as the embryo develops the cell begins to differentiate into different types of cells

Question 44

DNA

Answer 44

is a polymer made up of 2 strands that twist around to form a double helix ( this increases the surface area )

Question 45

understanding the human genome enabled us

Answer 45

- Search for genes linked with different types of diseases - improve understanding and treat inherited disorders - help trace the human migration pattern

Question 46

meiosis

Answer 46

a cell division in which the number of chromosome is halved and takes place in the reproductive organs eg testes an ovary

Question 47

why is meiosis important

Answer 47

it involves the fusion ( the process is known as fertilisation ) of the male and female gamete both containing half the number of chromosome (23) to produce offspring with the full number of chromosomes (46) this takes place in sexual reproduction