B13- Types of reproduction

Question 1

What is asexual reproduction?

-6

Answer 1

• occurs in fungi and bacteria and humans to replace worn out tissues
• 1 parent
• no fusion of gametes
• division by mitosis
• no differentiation in offspring
• offspring are clones of the parent

Question 2

What is sexual reproduction?

-3

Answer 2

• 2 parents
• gametes fuse and form a zygote
• variation in offspring

Question 3

What are human gametes and plant gametes?

Answer 3

human: egg and sperm
plant: egg and pollen

Question 4

How are gamete chromosomes different to human chromosomes?

Answer 4

normal cells have 23 pairs whereas gamete have 23 individual chromsomes

Question 5

Where does meiosis take place?

Answer 5

reproductive organs

Question 6

What happens during meiosis?

Answer 6

In meiosis, the starting cell has 48 chromosomes. first all the chromosomes are copied and pairs line up in the middle of the cell.

The cell then divides into two. These cells have the same amount of chromosomes as the starting cell

These cells divide one more time meaning there are now half the number of chromosomes and this forms the gametes. Chromosomes are single not pairs. Each 4 gametes ae genetically different

Question 7

What happens to the gametes after meiosis?

Answer 7

gametes join together in fertilisation and they fuse forming a cell with the normal number of chromosomes. The new cells divide via mitosis forming clones until it forms an embryo.

Question 8

Which reproduction produces variation in offspring?

Answer 8

sexual

Question 9

Why is variation good?

Answer 9

increases chances of surviving a change to the environment

Question 10

What are the advantages of asexual reproduction?

Answer 10

• 1 parent so less time and energy wasted on finding a partner
• faster

Question 11

What is the order in size of genome?

Answer 11

DNA, gene, chromosome, genome

Question 12

What is the process of protein synthesis?

Answer 12

2 stages- transcription (nucleus) and translation (cytoplasm).
base sequence of the DNA is copied to a complementary base molecule forming a template called mRNA (single strand)

mRNA leaves the nucleus into the cytoplasm and attaches itself to a ribosome where translation occurs. Amino acids are brought to the carrier molecules called tRNA and the ribosomes read triplets of bases forming amino acids. it uses this to join the correct amino acids to the correct bases. Once completed it folds into the unique shape