B6 Inheritance, Variation and Evolution Flashcards
What are the male and female gametes in humans? (and flowering plants)
Sperm and egg (pollen and egg).
What is the difference between sexual and asexual reproduction?
Sexual ? 2 parents so offspring genetically different. Asexual ? 1 parent so genetically identical offspring (clones).
What is meiosis?
Used to make gametes ? 1 cell divides twice. Makes 4 genetically different cells with only half the number of chromosomes.
Where in the cell is the genetic material found?
Nucleus
What is a gene?
A section of DNA that codes for a particular protein
What is a mutation?
A change in a gene (happen all the time ?most have no obvious effect)
What is a genome?
All of the genetic material of an organism.
Give 3 reasons why it is important to understand the human genome.
Find genes linked to diseases, understand inherited disorders, trace human migration patterns.
What is an allele?
Different types of a gene e.g. B ? allele for brown hair b- allele for blond
What do heterozygous and homozygous mean?
Heterozygous ? has 2 different alleles for a gene e.g. Bb Homozygous ? has 2 identical alleles for a gene e.g. BB or bb
What is the difference between genotype and phenotype?
Genotype ? the genes you have e.g. Bb. Phenotype ? what you look like e.g. brown hair
What are the genotypes for male and female?
Male = XY Female = XX
What is natural selection?
- There is wide variation in all species. 2. The ones best adapted to their environment will survive and reproduce. 3. Their genes (which made them best adapted) are passed on.
What is evolution?
Gradual changing of an organism over time due to natural selection.
What evidence do we have for evolution?
Fossils and antibiotic resistance in bacteria.
What is selective breeding?
When humans select parents to breed to produce offspring with desired characteristics.
What is genetic engineering?
When genes are inserted into an organisms genome to give a desired characteristic.
What are GM crops?
They have been genetically engineered e.g. so insects stop eating them.
Give 3 ways that fossils can be formed.
- Parts of organism doesn?t decay 2. Parts of an organism are replaced by minerals as they decay 3. Traces of animals or plants like footprints and burrows are preserved.
Give 3 ways extinction could happen.
E.g. change of environment, lack of food, new predator, new diseases.
How does antibiotic resistance happen?
Mutations cause some bacteria to not be killed by antibiotics (resistant). They survive and reproduce and therefore spread.
How can we prevent antibiotic resistance?
Don?t take antibiotics for viral illnesses. Take the whole course of tablets.
What are the 3 domains that organisms can be classified into?
Archaea (v primitive), Bacteria, Eukarya (plant and animals etc.)
