6 Inheritance variation and evolution - Inheritance 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
What is a chromosome?
A thread-like structure which contains coiled up DNA and proteins.
What is an allele?
A different version of a gene.
What does the term ?dominant? mean?
The individual only needs one copy of this allele for its phenotype to be seen.
What does the term ?recessive? mean?
The individual needs two copies of this allele for its phenotype to be seen.
What does the term ?homozygous? mean?
The individual has two identical alleles for this gene.
What does the term ?heterozygous? mean?
The individual has two different alleles for this gene.
What is a genotype?
The genetic makeup of an organism for a particular gene (e.g. RR).
What is a phenotype?
The displayed characteristic due to the interactions between alleles (e.g. red flowers).
How many pairs of chromosomes does an ordinary human body cell have?
23
How many pairs of chromosomes determine the sex of the individual?
1
What is the genotype of a female?
XX
What is the genotype of a male?
XY
What is polydactyly?
A condition that causes the individual to have extra fingers or toes.
Is polydactyly a dominant or recessive condition?
Dominant.
State the genotype(s) that would result in polydactyly.
PP or Pp (homozygous dominant or heterozygous for this gene).
What is cystic fibrosis?
A condition which causes sticky mucus to build up in the lungs.
Is cystic fibrosis a dominant or recessive condition?
Recessive.
State the genotype(s) that would result in cystic fibrosis.
cc (homozygous recessive).
State one method of screening embryos.
Amniocentesis/Chorionic villus sampling/IVF
State one concern of screening embryos.
Causing miscarriage/Ethical concerns/Inaccurate results/Expensive
State one benefit of embryo screening.
Know if child will have disorder/Able to decide if proceed with pregnancy or abortion
