Genetics Flashcards
Define Sexual reproduction
Genetic Infomation
How is meiosis different to mitosis.
It doesn’t produce identical cells
How many divisions are involved in meiosis?
2
How many daughter cells are produced by meiosis?
4
How many bases are there in DNA?
4
What are the names of the bases in the DNA?
Adenine, thymine, cytosine and guanine
Name the 2 complementary base pairings.
A with T, C with G
What are the complementary base pairings joined together with?
Weak Hydrogen Bonds
Define a Chromosome
Long coiled up molecules of DNA found the nucleus of eukaryotic cells.
Define a Gene.
A section of DNA that codes for a particular protein.
What is an organism’s genome
All of an organism’s DNA.
Why do you use detergent when extracting DNA from cells?
It breaks down the cell membranes to release the DNA.
Why do you use salt when extracting DNA from cells?
It makes the DNA stick together.
Where does DNA transcription take place?
The Nucleus
Briefly describe how transcription happens.
1) RNA polymerase binds to a region of non-coding DNA in front of a gene.
2) The 2 DNA strands unzip and the RNA polymerase moves along one of the strands of DNA.
3) It uses the coding DNA in the gene as a template to make the mRNA. Base pairing makes sure each is complementary to each other.
4) The mRNA molecule moves out of the nucleus into the cytoplasm.
Which base become Uracil in the mRNA?
Thymine
Where does DNA translation take place?
In the ribosomes
Briefly describe how translation happens?
1) Amino Acids are brought to the ribosome by tRNA
2) The order in which the amino acids are brought to the ribosome matches the order of the base triplets in the mRNA. These are known as codons.
3) The anticodon is complementary to the codon for the amino acids.
4) The amino acids are joined together by the ribosome. This makes a polypeptide molecule.
What did Mendel do with pea plants?
Crossed 2 pea pants of different heights then bred 2 of the offspring to find that there was a 25% chance of a pea plant in this generation to be small.
What 3 important conclusions did Mendel reach?
1) Characteristics in plants are determined by ‘hereditary units’
2) Hereditary units are passed on to offspring from both parents, one from each
3) Hereditary units can be recessive or dominant.
What do we now call Mendel’s ‘hereditary units’?
Genes
Why were Mendel’s experiments not recognised at the time?
Lack of prior knowledge of DNA, genes and chromosomes
What is an allele?
A different version of the same gene
Give an Example of a homozygous and heterozygous pair.
Homo- GG, gg, KK, kk etc
Hetro- Tt, Rr, Gg, Vv, Hh
