B6

Question 1

what does DNA stand for?

Answer 1

deoxyribonucleic acid

Question 2

what does DNA contain?

Answer 2

coded information that determines what inherited characteristics you have.

Question 3

where is your DNA found?

Answer 3

in the nucleus of animal and plant cells in very long structures called chromosomes.

Question 4

what is the structure of a DNA strand called?

Answer 4

a double helix

Question 5

what does each gene code for and what does it DNA do to contribute to it?

Answer 5

each gene codes for a specific sequence of amino acids which put together to make a specific protein. DNA determine what proteins the cell produces.

Question 6

what is a genome?

Answer 6

a term for the entire set of genetic material in an organism.

Question 7

in what ways is the understanding of human genomes an important tool for science and medicine?

Answer 7

• allows scientists to identify genomes linked to disease and could help develop new treatments
• scientists can look at genomes and trace the migration patterns of populations.

Question 8

in sexual reproduction, the mother and father produce gametes through what process?

Answer 8

meiosis

Question 9

why does a human offspring inherit features from both parents?

Answer 9

because it retrieves a mixture of chromosomes from both parents (23 from each fuse together to create a full pair of 46)

Question 10

in asexual production, what is produced? why?

Answer 10

genetically identical cells.
because there’s only one parent so the new cell has exactly the same genetic information as the parent cell. this is called a clone of the parent.

Question 11

describe the process of meiosis.

Answer 11

• before the cell divides and duplicates, its genetic information forms two armed crossbones which arrange themselves into pairs. (in the centre)
• in the first division, the pairs are pulled apart so each new cell only has one copy of each chromosome (some mother some father)
• in the second division, the chromosomes are pulled apart
• in the end, you have four gametes, each only a single set of chromosomes. they’re all genetically indifferent.

Question 12

what chromosomes do men have and what chromosomes do women have?

Answer 12

men- XY

women- XX

Question 13

what are alleles?

Answer 13

different forms of the same gene which can be dominant or recessive.

Question 14

what is the different between homozygous and heterozygous?

Answer 14

homozygous- when two alleles for a particular gene are the same
heterozygous- if two sets of alleles for a particular gene are different.

Question 15

what are the two different alleles? what do they determine?

Answer 15

dominant allele- even if the two alleles are different, the dominant allele still determines the traits (Bb or BB)
recessive allele- allele must be present in both chromosomes for it to develop (bb)

Question 16

what is a genotype?

Answer 16

the combination of alleles and genes an organism has

Question 17

what is a phenotype?

Answer 17

the result of your genotype. when your allele work ay a molecular level to determine what characteristics you have.

Question 18

what is an inherited disorder caused by a recessive allele?

Answer 18

cystic fibrosis- genetic disorder of the cell membrane

Question 19

what does cystic fibrosis cause and how common is it?

Answer 19

causes a thick sticky mucus in the air passages and pancreas. its carried by 1 in 25 people however is very rare as it requires both parents to have the gene for it.

Question 20

what is an inherited disease caused by a dominant allele?

Answer 20

polydactyly- born with extra fingers or toes

Question 21

what is polydactyly and how common is it?

Answer 21

genetic disorder meaning you are born with extra fingers of toes. more common as it only requires one parent to pass it down.

Question 22

what can embryos be screened for during in vitro fertilisation (IVF)? And how?

Answer 22

genetic disorders

by removing a cell from each embryo to analyse its genes.

Question 23

what are some ethical or moral concerns surrounding embryonic screening.

Answer 23

• implies that people with genetic disorder are undesirable which could lead to prejudice
• people believe IVF is done so people can choose their most desired child
• screenings expensive

Question 24

why are some people supportive of IVF?

Answer 24

• helps to stop people suffering
• treating disorders costs the gov. and tax payers a lot of money
• there are laws preventing extremes e.g what sex you baby is.

Question 25

what is genetic variation cause by?

Answer 25

your genotype (all the alleles and genes an organism has) which effects the phenotype (displays your characteristics)

Question 26

what are mutations?

Answer 26

a random change in the organisms DNA that can be inherited. it causes a change I’m the genome (gene is altered)

Question 27

what is Darwins Theory Of Evolution?

Answer 27

that all of todays speeches have evolved from simple life forms that first started to develop 3 billion years ago

Question 28

what is the development of new species called?

Answer 28

speciation (phenotypes changes so much due to natural selection that a completely new species is formed.

Question 29

what does extinction mean?

Answer 29

when no individuals of a species remain.

Question 30

what are some reasons for species to become extinct?

Answer 30

• quick changes in the environment
• new predators
• new diseases
• cant compete with other new species for food
• a natural disaster or catastrophic event.