Unit 6 biology Flashcards
How many chromosomes are there in gametes. How many in a normal body cell
- 46
What are the human male and female animal gametes
Male: sperm cell
Female: egg cell
What are the human male and female plant gametes
Male: Pollen
Female: Egg cell
Describe the process of meiosis
-The cell makes copies of its chromosomes to double the genetic material.
-The cell divides to get 2 cells and then it divides again to get 4, genetically different cells.
Why do gametes only have 23 chromosomes
They combine with the opposite sex gamete to make a full 46 chromosomes
Describe the features of asexual reproduction
-one parent
-genetically identical offspring
- cells divide by mitosis
Describe how malaria uses both types of reproduction
-Inside of the mosquito, the malaria reproduces sexually so there can be genetic mutations to make it more deadly
-Inside a human, it reproduces asexually to spread more quickly
Advantages of sexual reproduction
-Sexual reproduction produces variation in offspring
-Variation increases the chance of species survival when unfavourable conditions occur.
- allows for selective breeding where we takes the best traits from a species to make it stronger
Advantages of asexual on reproduction
-only one parent is needed
-can produce offspring quickly in favourable conditions
-uses less energy as no mate is needed to find
Describe how plants can use both sexual and asexual reproduction
- pollen can reproduce with the egg cells to make sexual reproduction
-plants like strawberries can use runners where new plants can grow from the ends of the runner
-daffodil bulbs are asexual as the offspring are identical
Why is the genetic material in the nucleus made up of
DNA (deoxyribonucleic acid)
Describe the structure of DNA
Double helix shape
Why is DNA made up of
Genes which are made up of nucleotides
What is in a nucleotide
A phosphate, a sugar and a base
What is the human genome
The genetic coding for all proteins in a organism
