Semester 2 Exam Revision Flashcards
Science
Define ‘allele’
Different versions of a gene
Define ‘dominant’
An allele that is displayed.
Define ‘recessive’
An allele that is masked by a dominant trait, unless you receive two.
Define ‘heterozygous’
When a person possesses two different alleles.
Define ‘homozygous’
When a person possesses two of the same alleles.
Define ‘genotype’
The alleles inherited for a gene.
Define ‘phenotype’
Observable traits as a result of the genotype.
Where is DNA found and why is it important?
Cell Nucleus - carries the genetic information that controls cell growth and development
Define ‘haploid’
Cell containing one set of chromosomes
Define ‘diploid’
Cell containing two sets of chromosomes
Define ‘gamete’
Sex cells - sperm or ova
Define ‘gonad’
An organ that produces and releases eggs or sperm
Define ‘karyotype’
The general appearance of a complete set of chromosomes in the cells of a species
What can we tell from a karyotype?
Genetic abnormalities in chromosome structure
Describe the process of Mitosis
- Occurs in all body/somatic cells
-Stages of Prophase, metaphase, anaphase, telophase - The cells produced are identical to the parent cell
- Produces 2 cells that have 46 chromosomes
- 1 round of cell division
What is the purpose of mitosis?
- The purpose is for the growth, repair and replacement of cells
Describe the process of meiosis
- Occurs in the gonads (sex organs)
- The cells produced are not genetically identical to the parent cell
- 2 rounds of division
- Daughter cells have 23 chromosomes
What is the purpose of meiosis?
The purpose is to produce sex cells for sexual reproduction
Define ‘variation’
The differences between individuals of the same species due to genetic and environmental factors.
Define ‘species’
An organism’s ability to successfully reproduce fertile offspring
Define ‘adaptation’
Genetic variation that increases chances of survival in an environment
Define ‘evolution’
The change in the characteristics of a species over generations.
Define ‘selective pressure’
An environmental factor that favours a particular trait.
Define ‘artificial selection’
The identification of desired traits in animals/ plants.
Define ‘speciation’
The formation of new species
Describe the natural selection process
- Genetic variation in a population due to a selective pressure or mutation.
- Survivors have a greater chance of mating and passing on inherited traits to their offspring.
- Species with the favourable gene will survive and those without will be hunted.
- Offspring are better suited & will become greater in the population.
Define ‘homologous structures’
They have different functions, but the same basic structure.
The similarity in anatomy results from recent common ancestry.
Define ‘big bang theory’
A theory that all matter and energy in the universe began expanding in all directions 10 to 15 billion years ago.
Define ‘red shift’
Light moving towards an observer shows a longer wavelength and lower frequency
Define ‘blue shift’
Light moving towards from an observer shows a shorter wavelength and high frequency