Year 11 Chapters 12

Question 1

What is in asexual reproduction?

Answer 1

• It only involves one parent
• The cells divide by mitosis
• There is no joining of specialised sex cells (gametes)
• There is no mixing of genetic information
• The offspring are known as ‘clones’
• There is NO VARIATION in the offspring

Question 2

What are gametes ?

Answer 2

• Specialised sex cells
• e.g. sperm or egg cell
• They contain one set of chromosomes, 23
• All gametes are genetically different

Question 3

What is in sexual reproduction?

Answer 3

• There are two parents
• Involves a male sex cell and a female sex cell
• The two gametes fuse together
• Gametes are fused in a special cell division know as meiosis
• There IS VARIATION in the offspring

Question 4

What is meiosis?

Answer 4

• This type of cell division produces cells with half the number of chromosomes a the parent cells
• This allows for two gametes to fuse together and create a zygote containing the correct number of chromosomes (23 from each parent)
• This allows for variation

Question 5

What is the genome ?

Answer 5

It is the entire genetic material of that organism

Question 6

What is DNA?

Answer 6

• It is a double stranded helix molecule
• It is made of a polymer which are two strands joined together
• It is found in all cell nucleus’s

-DNA = Deoxyribonucleic acid

Question 7

What are genes?

Answer 7

• Genes are small sections of chromosomes that code for a particular characteristic (proteins)
• They contain a code that contains sequence of an amino acid chain
• The sequence of amino acids male a protein

Question 8

Why study the human genome ?

Answer 8

• To find diseases linked to certain genes

- To understand and treat inherited disorders

Question 9

What is an allele?

Answer 9

• It is a form of gene
• Each allele codes for a different protein
• The combination of alleles you inherit will determine your characteristics

Question 10

What is homozygous?

Answer 10

• If you have two identical alleles for the same gene

- E.g. BB or bb

Question 11

What is heterozygous ?

Answer 11

• If you have two different alleles for the same gene

- E.g. Bb

Question 12

What is the phenotype ?

Answer 12

• It describes the physical appearance of an individual regarding a particular characteristic
• E.g. brown or green eyes

Question 13

What is the breakdown of chromosomes in each set used for?

Answer 13

• Each set of chromosomes contains 23 chromosomes
• 22 of this set control body characteristics
• The last one is used to determine gender
• A female has two identical chromosomes (XX), whereas a male has two different (XY)

Question 14

What is a dominant allele?

Answer 14

• It is the normal allele
• It is shown with a capital letter
• E.g. for cystic fibrosis : C = dominant allele (normal metabolism)

Question 15

What is a recessive allele?

Answer 15

• It is the faulty allele of the allele containing the disorder
• It is shown with a lower case letter
• E.g. for cystic fibrosis: c = recessive allele (cystic fibrosis)