Chapter 10 Inheritance of Characterstics and Genetic engineering

Question 1

how many chromosomes does the body cells have

Answer 1

they have 23 pairs of chromosomes each of which contains a DNA molecule

Question 2

what is DNA divided into

Answer 2

DNA can be divided into a large number of genes each of which codes for a particular protein

Question 3

what do females have

Answer 3

females have 22 pair of chromosomes plus 2 X chromosomes

Question 4

what do males have

Answer 4

males have 22 pair of chromosomes plus one X and one Y chromosome

Question 5

the Y chromosomes is not …

Answer 5

genetically identical to the X chromosome

Question 6

what is mitosis

Answer 6

in the division of body cells mitosis ensures that exact copies of the chromosomes are passed to 2 daughter cells which are genetically identical

Question 7

what is meiosis

Answer 7

during gamete formation 4 cells are produced by meiosis each of which contains half the number of chromosomes

Question 8

gametes are all

Answer 8

genetically different

Question 9

what do the chromosomes carry

Answer 9

the genetic information form parents to offspring

Question 10

what is a change in a chromosome or single gene called

Answer 10

a mutation

Question 11

what does a mutation result in

Answer 11

loss of an enzyme, which disrupts the cells chemical reactions or its structure the effect may be minor but could lead to genetic disorders

Question 12

how are characteristics inherited

Answer 12

through the chromosomes which are passed on from the mother and father, the offspring receives a mixture of genes from both parents

Question 13

allele 
genotype
phenotype
homozygous
heterozygous 
dominant 
recessive

Answer 13

allele - different version of the same gene
genotype - the genes you have
phenotype - the characteristics that are displayed
homozygous - two alleles the same
heterozygous - two alleles different
dominant - only one needs to be present for it to be expressed
recessive - 2 needs to the present for it to be expressed

Question 14

what can alter a charactersitc

Answer 14

lifestyle - diet and exercise

Question 15

how are sex link cells inherited

Answer 15

through the mother, fathers cannot pass a sex linked disorder to their sons because the boys inherit y chromosomes

Question 16

why might disorders that usually appear in males but can appear in females

Answer 16

if a boy has an x chromosome that has a mutated allele then he will have the disorder even though its recessive
if the girl has one fauty allele she will also have the normal dominat allele and wont develop the disorder
colour blindness
haemophilia - blood does not clot properly
muscular dystrophy - the muscles gradually degenerate

Question 17

some disorders can be down to

Answer 17

the loss or duplication of part of or a whole chromosome

Question 18

insulin thing

Answer 18

a human gene can be transferred to bacterial DNA using specific enzymes and the process can be sued to manufacture hormones such as insulin and vaccines

Question 19

experimental techniques

Answer 19

genes can be transferred to human cells in gene therapy to treat diseases like cystic fibrosis
stem cells can be sued to replace damaged tissue

Question 20

what are the benefits of genetic engineering

Answer 20

• get rid of disorders

- slippery slope

Question 21

what are the benefits of gene therapy

Answer 21

• problems occur
• expensive
• stop genetic disorders

Question 22

what are the benefits of stem cell therapy

Answer 22

• get rid of genetic disorders

Question 23

what are the benefits of embryo screening

Answer 23

• get rid of genetic disorders

- cost the government a lot of money

Question 24

what is huntingtons disease

Answer 24

it causes degeneration of brain cells

dominant allele

Question 25

what is cystic fibrosis

Answer 25

its a genetic disorder where the person produces a very thick sticky mucus
recessive disorder

Question 26

what do genetic counsellors do

Answer 26

these are health professionals who use their understanding of the mechanisms of inheritance to advise parents on the chances of a child being born with a genetic disorder