B6

Question 1

Process of meiosis

Answer 1

1) Chromosomes in diploid cell are copied
2) Similar chromosomes pair up and genes are swapped between them.
3) Cell divides to produce 2 diploid cells.
4) These cells divide again to produce 4 haploid cells (gametes)

Question 2

Asexual Reproduction

Answer 2

Plants can reproduce both sexually and asexually.
- Asexual reproduction happens via mitosis; daughter cells are identical - clones (no fusion of gametes)

Question 3

Advantages of asexual reproduction

Answer 3

• population can rapidly increase
• only one organism needed for reproduction

Question 4

Disadvantages of asexual reproduction

Answer 4

-no genetic diversity
-difficulty to adapt to environments

Question 5

Sexual reproduction advantage

Answer 5

-Can become better adapted to environment.

Question 6

Description of DNA

Answer 6

DNA is a double helix polymer that stores genetic code.

Question 7

DNA Key Terms

Answer 7

Phenotype; expression of genotype in physical characteristics
Genotype; specific genetic code
Gene; portion of DNA that codes for a protein (by mapping these it allows us to find out the causes of disorders).
Genome; entire genetic make-up of any organism

Question 8

What is an allele?

Answer 8

Different versions of the same gene
- Dominant alleles are expressed over recessive alleles
- For a recessive allele to be presents in the phenotype, there must be no dominant allele. (E.G, ‘bb’)

Question 9

What is a homozygous allele?

Answer 9

2 alleles that are the same
E.G, ‘bb’, ‘BB’

Question 10

What is a heterozygous allele?

Answer 10

2 alleles that are different
E.g, ‘Bb’

Question 11

Polydactyly and CF

Answer 11

-Polydactyly is caused by a dominant allele
-Cystic Fibrosis is caused by a recessive gene

Question 12

What is Darwin’s theory of evolution?

Answer 12

Random mutations results in mutation, some organisms are better adapted - those better adapted are more likely to survive.

Question 13

What is Lamarck’s theory of evolution?

Answer 13

mutations/adaptations are a result of environment affecting characteristics inherited by offspring and so it cannot be random.

Question 14

Antibiotic resistant bacteria

Answer 14

used as evidence for Darwinian evolution; if not all bacteria are killed, those most resistant will reproduce.

Question 15

What is selective breeding?

Answer 15

Breeding organisms that have desired characteristics to produce offspring in which the characteristics are more pronounced.

Question 16

What is genetic engineering?

Answer 16

The insertion of a gene into an organism’s genome so it synthesises a specific protein to achieve a desired characteristic.

Question 17

Process of GE

Answer 17

1) Desired gene is cut using enzymes
2) Gene inserted into a vector (bacteria/plasmid)
3) Vector inserts gene into cells of another organism early in development
4) Organism develops with desired characteristic due to every cell synthesising that specific protein.

Question 18

Classification System in order

Answer 18

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 19

Types of domain

Answer 19

Archaea (found in extreme conditions - extremophiles)
Bacteria
Eukaryote

Question 20

Binomial Names

Answer 20

Genus + Species