Inheritance and Variation- Paper 2 Flashcards
By which cell division type does asexual reproduction rely on?
Mitosis
How are gametes formed?
Meiosis
How is a gamete different from a normal body cell?
Half genetic information - haploid
Name the structure formed by fertilisation (fusion of male and female gametes).
Zygote
State one difference between asexual and sexual reproduction.
A: no fertilisation/genetically identical offspring; S: fertilisation/genetic variation
Name the gametes in plants.
Egg + Pollen
Name the organ that produces egg cells.
Ovaries
Name the organ that produces sperm cells.
Testes
How many divisions do a cell undergo in meiosis?
Twice
Name the process where a sperm and an egg cell fuse together.
Fertilisation
How many chromosomes are there in a human gamete?
23
Define ‘gametes’.
Sex cells
Name the gametes in animals.
Sperm & egg
Describe the cells produced by meiosis.
4 cells, genetically different.
Describe the cells produced by mitosis.
2 cells, genetically identical (clones).
State the three key steps in meiosis.
- Copies of the DNA are made.
- The cell divides twice to form 4 gametes, each with a single set of chromosomes.
- All 4 cells are genetically different from each other.
When a new cell is formed through fertilisation, how does it divide?
Mitosis.
The genetic material in the nucleus of a cell is?.
DNA
Describe the structure of DNA.
A polymer made up of two strands forming a double helix.
Name the structure within which DNA is contained.
Chromosomes.
What is a gene?
A small section of DNA on a chromosome.
What is the function of a gene?
To code for a particular sequence of amino acids in order to make a specific protein.
What is a genome?
The entire genetic material of an organism.
State 3 ways in which understanding of the human genome will be important.
- To search for genes linked to different types of disease
- To understand and treat inherited disorders
- To trace early human migration patterns