B5

Question 1

Definition of Genome

Answer 1

And organisms entire genetic material

Question 2

How is an organisms genetic material arranged ?

Answer 2

And organisms genetic material is arranged into coiled up chromosomes

Question 3

What is the gene ?

Answer 3

A gene is a short section chromosome which codes for protein

Question 4

What are alleles?

Answer 4

alleles are alternative forms of the same gene which gave a different form of the characteristic (e.g. blue/brown eyes)

Question 5

What are the differences between organisms within a species called ?

Answer 5

Differences within species are called variations

Question 6

Definition of genotype

Answer 6

and organisms genotype is all of the alleles that an organism has

Question 7

Definition of a phenotype

Answer 7

and organisms phenotype is the characteristics that it displays

Question 8

Which two factors affect an organisms phenotype ?

Answer 8

Organisms inherited genes can affect the phenotype and the interaction with the environment. Most variation is a mixture of both

Question 9

Definition of continuous variation

Answer 9

continues variation is organisms that vary within a range usually influenced by both genetic and environmental factors e.g. humans vary in all kinds of height

Question 10

Definition of discontinuous variation

Answer 10

discontinuous variation is when organisms can vary within two or more categories usually influenced by one gene e.g. humans have either blood-group A, B, AB or O

Question 11

What is a mutation ?

Answer 11

A mutation is when the sequence of DNA bases in the gene is changed which produces a genetic variant

Question 12

How likely are genetic mutations to affect the phenotype ?

Answer 12

Mostly genetic mutations have no effect on the phenotype , sometimes they have a small influence and rarely they determine the phenotype example cystic fibrosis

Question 13

What happens when a mutation occurs in coding DNA ?

Answer 13

The mutation occurs in coding DNA it could affect the structure of the protein substrate may no longer fit into the active site so it may no longer function

Question 14

What happens when a mutation occurs in non-coding DNA ?

Answer 14

If you mutation occurs in non-coding DNA it can affect how the genes expressed which means it can affect whether it is switched on or off this can stop the transcription of mRNA through that the protein is not produced at all

Question 15

How many pairs of chromosomes the normal human cells contain ?

Answer 15

Normal human cells contain 23 pairs of chromosomes

Question 16

Definition of a gamete

Answer 16

A gamete is the human sex cell with 23 single chromosomes

Question 17

How are gametes produced?

Answer 17

Gametes are produced using meiosis:

1) this cell has half of its chromosomes inherited from the organism’s father and half the chromosomes inherited from the organisms mother
2) the cell then duplicates its DNA it now has 46 pairs of chromosomes
3) the chromosomes then line up at the centre of the cell and cell fibres pull them apart
4) cell membranes form around the each set of chromosomes
5) the cytoplasm then divides
6) the chromosomes then line themselves at the centre of the cell again and cell fibres pull the arms apart
7) cell membranes form around the single chromosomes in each of the four cells
8) finally the cytoplasm splits and for haploid gametes have been produced which are all genetically different

Question 18

What happens during fertilisation

Answer 18

during fertilisation the mothers and the fathers gametes views to produce a fertilised egg which is diploid because it has a full set of chromosomes. The first like egg then undergoes mitosis and develops into an embryo which inherent characteristics from both parents because it’s received a mixture of chromosomes

Question 19

What is a sexual reproduction ?

Answer 19

Asexual reproduction is mitosis

Question 20

What are the advantages of asexual reproduction ?

Answer 20

Asexual reproduction produces lots of offspring very quickly (bacteria divide every half an hour) and only one parent is needed is an organism can reproduce when it’s favourable without having to find a mate

Question 21

What are the disadvantages of asexual reproduction

Answer 21

the disadvantages of asexual reproduction is that there is no genetic variation between offspring to the environment changes and conditions becomes unfavourable the whole population can be affected

Question 22

What are the advantages of sexual reproduction ?

Answer 22

Sexual reproduction increase genetic variation within the population which means of the environment conditions change is more likely that some individuals will have the characteristics which enable them to survive . This leads to evolutional overtime

Question 23

What are the disadvantages of sexual reproduction ?

Answer 23

The disadvantages of such reproduction is it takes more time and energy, produces fewer offspring and two parents are needed

Question 24

What is the allele displayed in the phenotype called ?

Answer 24

the allele displayed in the phenotype is called the dominant allele

Question 25

What is the allele that isn't displayed in the phenotype Called ?

Answer 25

The allele that isn't displayed in the phenotype is called the recessive allele

Question 26

Definition of homozygous

Answer 26

If you are homozygous both alleles for a trait are the same

Question 27

Definition of heterozygous

Answer 27

if you are heterozygous you have two different alleles for a trait

Question 28

What can we use to work out what possible traits a child will have?

Answer 28

Genetic diagrams are used to work out what possible traits a child will have

Question 29

Using both a punnet square and a genetic diagram show that it is a 50-50 chance of having a baby boy or baby girl

Answer 29

😊😊😊

Question 30

Describe the work of Mendel

Answer 30

Mendel used pea plants to investigate how genes inherited . First he took a tall pea plant and bread it with a dwarf pea plant. All the pea plants were tall. He then bred two of the offspring. 75% were tall and 25% were dwarf. From this he proved that characteristics were inherited and he proved inherited factors could be dominant (tall gene) or recessive (short gene). We now know his inherited factors are genes.

Question 31

Definition of artificial classification

Answer 31

artificial classification is placing organisms into groups based on observable features

Question 32

Natural classification definition

Answer 32

natural classification is placing animals into groups based on common ancestors using the five kingdoms and further subdivisions

Question 33

Name all the subdivisions in natural classification | Hint: King Philip came over for good soup

Answer 33

kingdom, phylum , class, order, family, genius, species

Question 34

Definition of a species

Answer 34

Species is a group of one type of organism able to reproduce to give fertile offspring

Question 35

How is an animal named ?

Answer 35

An animal is named using its genus followed by the species

Question 36

Which developments in biology have led to improvements in classification ?

Answer 36

DNA sequencing is now used to compare exactly how related organisms are using computer systems

Question 37

What is natural selection ?

Answer 37

Natural selection is the natural process of having organism evolves due to genetic variation of advantageous phenotypes

Question 38

Explain how natural selection has caused rabbits to evolve to have long ears

Answer 38

Rabbit used to have shorted , one day a mutation occurs to one rabbit which is born with long ears. This rabbit can hear predators better than the others it doesn't get eaten and is able to reproduce . His offspring may inherit this gene and are more likely to survive and reproduce overtime the whole population will have long ears

Question 39

What determines the speed in which species evolve ?

Answer 39

The speed in which a species evolves is determined by how quickly they reproduce

Question 40

What is speciation ?

Answer 40

Speciation is where a barrier between the population can cause part of the population to evolve so much that a new species is formed and cannot be bred with the old species to form fertile offspring

Question 41

Which two ways can we back up the theory of evolution ?

Answer 41

1) fossil records – also sound deep in the ground are usually older by placing them in chronological order gradual change is an organism can be observed which provide evidence for evolution 2) bacteria resistance – in any population mutations occur through the bacteria has a mutation which makes it resistant to an antibiotic it is extremely advantageous , this means it will survive when antibiotics are used and be able to multiply and pass on the beneficial phenotype so soon the whole population will be antibiotic resistant

Question 42

Explain how Darwin and Wallace came up with the theory of evolution by natural selection

Answer 42

Charles Darwin came up with the theory of evolution by natural selection all on his five year voyage . He observed how members of the same species had variations which are most suited to the environment you notice that this could be passed on. Wallace has noticed that warning colours are used by some species such as butterflies to deter predators from eating them and he came up with the idea of evolution by natural selection to explain this and wrote to Darwin for help . Darwin suggested they both write papers and present them simultaneously to the authorities however it was Darwin's famous book 'on the origin of species' that made other scientist pay attention to the theory so Darwin was better remembered them Wallace

Question 43

How has having an understanding of the revolution influenced modern biology ?

Answer 43

1) classification – organisms are now classified based on evolutionary relationships 2) antibiotic resistance – we understand the importance of finishing antibiotic courses to kill all remaining bacteria to those we don't kill don't become resistant 3) conservation – we understand that the changing environment can quickly cause species to go extinct if they don't have time to adapt so conservation projects like seed banks store seeds so if a plant does go extinct or adapts into a new species we can replant them