CB3 - Genetics Flashcards
What are the advantages and disadvantages of Asexual reproduction?
Advantages:
- Can produce offspring very quickly because of reproductive cycle
- Only one parent is needed and can reproduce without a mate
Disadvantages:
- No genetic variation between population so if any environment changes, conditions might affect whole population
What are the advantages and disadvantages of Sexual reproduction?
Advantages:
- Creates genetic variation which have different characteristics
- This can lead to natural selection and evolution
Disadvantages:
- Takes more time and a lot of energy
- You need two mates/parents and this can be a problem if they are isolated.
Describe cells produced by meiosis?
Produces 4 genetically different daughter cells (Gametes) and they are haploid cells
Why are haploid cells produced via meiosis?
When 2 gametes fuse, cell will have full genetic material.
Describe DNA as a polymer?
Made up of lots of repeating units called nucleotides. Each contain 1 sugar molecule, 1 phosphate molecule and 1 one base. There are 4 bases: A, T, C, and G. A pairs with T and C pairs with G. DNA has two strands coiled together in a shape of double helix. Complimentary bases are joined with weak hydrogen bonds.
What is a Genome?
Entire DNA of an organism.
What is a Gene?
A section of DNA which codes for a protein.
How can DNA be extracted from fruit?
- Mash some strawberries, put them in beaker containing detergent and salt and mix
- Filter mixture to get insoluble cell out
- Add some ice-cold alcohol to filter mixture
- DNA will come out solution as it is not soluble in cold alcohol. It will appear as white stringy precipitate.
Explain how order of bases in DNA decide order of amino acid in protein?
Section of DNA codes for particular protein. Each amino acid is coded by a sequence of 3 bases (Base triplet). Amino acid are joined together to make protein.
Explain what is Transcription?
RNA polymerase binds to a non-coding DNA in front of gene.
Two DNA strands unzip and RNA move along one strand.
Uses coding DNA in gene as template for mRNA. Base pairing between DNA and RNA to make sure mRNA is complimentary.
mRNA moves out the nucleus and joins with ribosomes.
Explain what is Translation?
Amino acids are brought by tRNA.
Order in which amino acid are brought matches of base triplets in mRNA (Codons).
tRNA structure is called an anticodon - Complimentary to codon for amino acid.
Amino acid are joined together and fold up into a polypeptide chain.
Describe how non-coding DNA affects binding of RNA polymerase?
If mutation in DNA it could affect ability of RNA to bind to it, might make it easier or harder. How well RNA binds affect how much mRNA is transcribed and how much protein is made. Depending of function of protein, phenotype may be affected.
Describe how coding DNA can affect sequence of amino acid?
If mutation in a gene, might code for a diff sequence of amino acid which can change shape of protein. Might change the Phenotype.
Describe the work of Mendel in discovering basis of genetics?
Crossed tall pea plants and dwarf pea plants - Offspring produced were al tall plants. Bred 2 tall plants and produce 3:1 tall to dwarf plants.
What had Mendel showed?
Characteristics were determined by separately inherited passed on from each parent. The ratio shows Tall was dominant.