inheritance and variation

Question 1

how many chromosomes do we have

Answer 1

23 pairs

46 individual

Question 2

which chromosome is mothers and which is father s

Answer 2

X= mum
Y = dad

Question 3

what is stage 1 of meiosis

Answer 3

replicate its structure

line up in the middle of the cell

chromosomes get pulled apart to seperate sides of the cell (DNA IS DIFFRENT)

Question 4

what is stage 2 of meiosis

Answer 4

they line up again in the new cells

each ARM gets pulled to opposite sides of the cell

they divide again to make 4 new gametes which are genetically unique from each other

Question 5

summarise meiosis

Answer 5

genetic info is copied

the cell divides twice to make 4 new gametes which each a single set of chromosomes

all gametes are genetically diffrent

Question 6

how do you genetically modify an organism

Answer 6

find an organism with a desired trait
take the gene out
transfer to another organism
modifies the organisms genome

Question 7

what are examples of things that have been genetically modified

Answer 7

CROPS - to become bigger and better fruits and to become resistant to disease and produce more yield

BACTERIAL CELLS- to produce insulin for diabetes

Question 8

what is gene therapy and the issues

Answer 8

treating inherited disorders by giving someone the healthy version of the gene

it’s difficult as the faulty gene would be in all cells and it’s difficult to transfer new gene to every cell

HOWEVER YOU COULD TRANSFER AT EARLY STAGE OF DEVELOPMENT INSTEAD

Question 9

what are the pros and cons of genetic engineering

Answer 9

pros
more yield, more crops with desired characteristics and resistance to disease (more food for less money), can have plants produce special nutrients

cons
don’t know how GM plants might affect our health

can outcompete other plants and change the whole ecosystem (unlikely)

Question 10

how do we transfer the gene to the cell

Answer 10

find the gene we want
cut out the DNA to isolate
insert DNA into virus or bacterial plasmid
organisms cells will take up the vector and the gene

it will start producing proteins

Question 11

how does naturual selection happen

Answer 11

individual organisms have a wide range of variation

organisms which have a desired characteristic will more likely survive and therefore breed more successfully

the characteristics will be passed on to their offspring

Question 12

why were charles darwin’s ideas not accepted

Answer 12

insufficient evidence

challenged religious beliefs that God created all life on earth

the mechanism of inheritance and variation had not been discovered

Question 13

what is the definition of evolution

Answer 13

the change in inherited characteristics through the process of natural selection

Question 14

reasons why species become extinct

Answer 14

loss of food
loss of habitat
new predators
competition
natural disasters
hunters
disease
environmental change

Question 15

what did alfred russel wallace discover

Answer 15

discovered same theory as darwin but also realised that closely related species were often separated by geographical barriers

Question 16

how do new species form

Answer 16

geographical barrier (e.g river) separates an organisms population into 2 groups

There is no interbreeding between the 2 groups

natural selection will favour diffrent alleles

any mutations can’t spread

population becomes to change

diffrent phenotypes make reproduction impossible

new species created

Question 17

how are fossils evidence for evolution

Answer 17

can see how organisms have developed over time

Question 18

how does an animal become a fossil

Answer 18

animal dies and falls into soft mud

mud or slit covers body

slit or mud gradually turns into rock encoding the body

hard parts replaced by minerals

soft parts do not fossilise well as they decay

earths movement causes remains to be exposed

Question 19

give an example of a fossil

Answer 19

casts
impressions( e.g footprints

Question 20

why were fossil records incomplete

Answer 20

many early life forms were soft bodied

Question 21

how may fossils be formed from

Answer 21

parts of organisms that have not decayed
parts of organisms being replaced by minerals
as preserved traces of organisms

Question 22

why can bacteria evolve

Answer 22

reproduce rapidly

Question 23

how does resistence occur

Answer 23

random mutations cause new strains. Some strains may be resistant and therefore survive the antibiotic. They then reproduce rapidly and create a colony of that resistant strain

Question 24

how do you reduce resistance of antibiotics

Answer 24

doctors shouldn’t prescribe antibiotics for non serious illnesses

patient complete the course of antibiotics so that all bacteria is killed and none can mutate

reduce agricultural use of antibiotics

Question 25

why can’t we keep up with new bacteria

Answer 25

the process of developing and making a new antibiotic is long and it’s expensive

Question 26

who discovered classification

Answer 26

carl linneas

Question 27

what are the 2 kingdoms

Answer 27

Plant and animal

Question 28

what is the hierarchy of organisms

Answer 28

kingdom phylum class order fungi genus species

Question 29

how do you remember it

Answer 29

King Prawn Curry OR Fat Greasy Sausage

Question 30

what does the binomial naming system consist of and what are the rules

Answer 30

genus and species genus is always capitalised at the first letter species is lower case BOTH ARE ITALISED

Question 31

what advances in biology has made an impact on classification system

Answer 31

microscopes- can look at internal structures three domain system

Question 32

what is the three domain system and who discovers it

Answer 32

CARL WOESE Archaea (primitive bacteria) bacteria (true bacteria) eukaryotia (which includes fungi protists plants and animals

Question 33

what are gametes

Answer 33

human sex cells (sperm and egg)

Question 34

what does meiosis produce

Answer 34

gametes

Question 35

what is the definition of sexual reproduction

Answer 35

fusion of male and female gametes

Question 36

what happens as a result of sexual reproduction

Answer 36

offspring receives genetic information from both parents which provides variation for the offspring

Question 37

what does a sexual reproduction involve

Answer 37

mitosis

Question 38

what are some differences of a sexual reproduction

Answer 38

it only involves 1 parent it dosent produce any variation in the offspring produces genetically identical clones dosent involve gametes no mixing of genetic information

Question 39

what are the advantages of SEXUAL reproduction

Answer 39

produces variation in offspring variation can increase survival chances for the offspring Gives species survival advantage by natural selection NATURAL SELECTION CAN BY SPED UP BY HUMANS BY SLECTIVE BREEDING TO INCREASE FOOD PRODUCTION

Question 40

ADVANTAGES OF A SEXUAL REPRODUCTION

Answer 40

Only one parent is needed more energy efficient quicker indentical offspring desirable genetics/ characteristics are passed on to the the offspring many offspring’s can be produced if conditions are favourable

Question 41

where is dna found

Answer 41

in the chromosomes chromosomes are found in the nucleus

Question 42

what is the structure of DNA (2 marks)

Answer 42

double helix structure contains A G C T bases

Question 43

what is a gene

Answer 43

small section of dna on a chromosome

Question 44

what is each gene code for

Answer 44

a specific protein

Question 45

what is a genome

Answer 45

entire genetic material in an organism

Question 46

what is the benefits of understanding the human genome

Answer 46

search for genes specifically linked to a type of disease understand and treat inherited disorders use in human migration patterns

Question 47

what is DNA

Answer 47

Polymer made up of 2 strands

Question 48

what is dna polymer called

Answer 48

nucleotides

Question 49

what are the three main parts of nucleotides

Answer 49

circle = PHOSPHATE group pentagon= sugar molecule rectangle = base

Question 50

are dna strands complementary

Answer 50

yes

Question 51

what bases are always linked together in A C G T

Answer 51

A - T and vise versa C- G and vice versa

Question 52

what are alleles

Answer 52

diffrent versions of genes

Question 53

what do genotypes tell us

Answer 53

what alleles are present

Question 54

what is homozygous

Answer 54

two of the same type of alleles (rr, RR)

Question 55

what is heterozygous

Answer 55

two diffrent alleles (Bb, bB)

Question 56

what is a phenotype

Answer 56

yells is the characteristics caused by a persons alleles

Question 57

how will a recessive allele shown

Answer 57

will only show in the phenotype if 2 copies are present

Question 58

does a dominant allele require 1 or 2 copies of the allele

Answer 58

1

Question 59

what is cystic fibrosis

Answer 59

ressesive disorder ( both parents must have the alleles) controlled by a single gene disorder of the cell membrane Cc = carrier but not affected CC= unaffected cc= cystic fibrosis however they are only probabilities so the real outcome can differ

Question 60

what is polydactyl

Answer 60

extra fingers or toes caused by a dominant allele will inherit even if only one parent carries it Pp= will have it PP= unaffected pp= has it so is more chance to get this than cystic fibrosis

Question 61

what is embryo screening and the issues around it

Answer 61

embryos are tested to see if they have a defected allele for inherited disorders embryos which do not have the alleles will be implanted into women FOR stops people suffering saving money for the government/ NHS there are laws to stop it going to far AGAINST screening is expensive- people think the money should be used elsewhere some embryos are destroyed - unethical in the future we may be able to screen their embryos so they can pick the most desirable one - unethical