Genetics Flashcards
What are the advantages of sexual reproduction?
Provides variation, species can adapt to new environments, a disease is less likely to spread.
What are the disadvantages to sexual reproduction?
Time and energy to find mate, it is not possible for an isolated individual.
What is asexual reproduction?
Involves only one parent, Organisms produced are exact replicas of their parents.
What are the advantages of asexual reproduction?
increase in population, only one parent needed, fast, more time and energy efficient.
What are the disadvantages of asexual reproduction?
no variation, species may be suited to only one habitat, disease may effect everyone.
What is meiosis?
meiosis produces haploid non-identical sex cells or gametes. These fuse to form a diploid fertilized egg cell.
What does meiosis produce?
- sperm, egg cells in animals and pollen
- pollen and egg cells in plants
What is mitosis?
mitosis produces identical diploid cells for growth and repair
What are chromosomes?
These are long threads of DNA, which are made up of genes.
What are genes?
a gene is a small section of DNA, each gene codes for a particular sequence of amino acids.
What is a genome?
the genome is one copy of all an organisms DNA.
Who found out the structure of DNA?
James Watson and Francis Crick in 1953.
What does DNA look like?
two strands coiled into a double helix.
How is DNA structured?
DNA is a polymer made from four different nucleotides. These are arranged in a repeating fashion.
What is the repeating pattern of the four nucleotides in DNA?
T-A , C-G , A-T, C-G, T-A, G-C
What nucleotides pair up with eachother?
thymine pairs with adenine
guanine pairs with cytosine.
Where is the DNA code for protein?
The Nucleus
How do cells express their genes?
by converting the genetic message into protein. This process of protein synthesis occurs in two stages - transcription and translation.
What is mutation?
A mutation is a change in a gene or chromosome
What is natural selection?
organisms that are better adapted to an environment are more likely to survive long enough to reproduce and pass on their genes. This leads to evolution
What are the causes of mutation?
- ionising radiation
- chemical mutagen, such as tar from cigarette smoke
What are the effects of a mutation?
change the activity of a protein if they occur within a gene.
What are homozygous?
two of the same alleles
What is a Genotype?
the alleles that an organism has.
