Topic 3 Using Spec

Question 1

What are the advantages of asexual reproduction

Answer 1

Lots of identical offspring
Faster
No mate

Question 2

In terms of speed why is asexual reproduction an advantage

Answer 2

As the reproduction is faster than sexual reproduction

Question 3

In terms of mating why is asexual reproduction an advantage

Answer 3

No mate is required therefore asexual reproduction is more efficient in regards to time and energy

Question 4

Why is lots of identical offsprings an advantage of asexual reproduction

Answer 4

As if conditions are favourable, producing lots of identical offspring is positive

Question 5

What is a disadvantage of asexual reproduction

Answer 5

As there are identical offsprings there isn’t a lot of variation in the population

Question 6

What are the advantages of sexual reproduction

Answer 6

Variation in offspring

Artificial selection

Question 7

In terms of variation of offspring , where is this an advantage to sexual repeat

Answer 7

As the offsprings aren’t identical the chances of population being able to survive environment change by natural selection increases as some individuals are likely to be adapted to the new conditions

Question 8

Why is mating a disadvantage within sexual reproduction

Answer 8

As it requires time and energy to find a mate to produce and offspring

Question 9

Explain the role of meotic cell division including chromosome info
Step 1

Answer 9

Cells split - each cell has pair of each chromosome (diploid cell)
During Melissa each pair of chromosome replicate and the cell splits in two

Question 10

Step 2 of meotic division

Answer 10

There are now two identical cells

The diploid cell divides again

Question 11

Step 3 of meotic division

Answer 11

4 genetically different gametes that have half the number of chromosomes of the parent cell are created
Cells that have 1 copy of each chromosome are haploid cells

Question 12

Step 4

Answer 12

The gametes then fertilise

Question 13

Describe the dna structure in terms of polymers

Answer 13

Double helix polymer
Two strands coiled together to form the double helix
The strands are linked by complimentary base pairs - adenine thymine and cytosine guanine
They are held together by weak hydrogen bonds

Question 14

What is a gene

Answer 14

A small section of dna which codes for a sequence of amino acids, which then combine to give a specific protein

Question 15

What is a nucleotide

Answer 15

consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.

Question 16

What are the three components nucleotides are made up of

Answer 16

A sugar
A phosphate
A base attached to the sugar

Question 17

How can dna be extracted from fruit

Answer 17

1) Grind a sample of fruit (such as strawberry) in soapy water to break open the cells which releases the dna
2) filter the sample to produce a filtrate
3) Very slowly, pour ice-cold ethanol into the filtrate.The DNA moves into the ethanol by precipitation, and can then be removed with a wire loop.

Question 18

how does the order of bases in a section of DNA decides the order of amino acids in the protein and that these fold to produce specifically shaped proteins such as enzymes

Answer 18

Order of bases on dna tells us the order for combining amino acids to create certain proteins
Can change the protein made by a gene by altering the sequence of bases in the gene
This is because the order of amino acids changes how a protein folds together, which affects its structure and function.

Question 19

What two stages does protein synthesis happen in

Answer 19

Transpiration and translation

Question 20

What happens in transcription

Answer 20

Double stranded dna is unzipped and one strand is used to make a templates of dna code in form of mRNA
Enzyme rna polymerase joins mRNA template
mRNA template leaves nucleus

Question 21

What happens in translation

Answer 21

mRNA template used to guide protein synthesis on ribosomes located in the cytoplasm
Specific amino acids are delivered by tRNA to add to the forming protein change

Question 22

What is a phenotype

Answer 22

Set of observable characteristics of an individual

Question 23

Describe the work of Mendel in discovering the basis of genetics

Answer 23

Preformed breeding experiments on pea plants - showed characteristics were determined by inherited units

Question 24

What happened in the 20th century with mendels work

Answer 24

The similarity between the behaviour of chromosomes and Mendel’s ‘units’ was recognised.
Consequently, it was decided that the ‘units’ were located on chromosomes.
Additionally, the ‘units’ were renamed genes.

Question 25

What is an allele

Answer 25

Different forms of the same gene

Question 26

What is the dominant allele

Answer 26

Represented by a capital letter eg B (brown eyes)

If someone has a copy of B allele they will have brown eyes no matter what other allele is present

Question 27

What is a recessive allele

Answer 27

Has to have two copies of allele eg bb
if b was blue eyes
A person can only have blue eyes if both of their alleles are b.

Question 28

What is a genotype

Answer 28

Combination of alleles an organism has

Question 29

When is a heterozygous?

Answer 29

if two alleles are different eg Bb

Question 30

When is a person homozygous?

Answer 30

If the two alleles ade the same eg BB or bb

Question 31

What is monohybrid inheritance

Answer 31

inheritance of traits determined by a single gene.

Question 32

What colour could pea plants be

Answer 32

Green or yellow

Question 33

What is the probability (%) of recessive phenotype in the offspring of parents with genes Gg and Gg?

Answer 33

25%

Question 34

How many pairs of chromosomes are responsible for determine sex

Answer 34

1 they are called X amd Y

Question 35

What letters are males

Answer 35

XY

Question 36

What letter are females

Answer 36

XX