Biology test 3 Flashcards
What are the three steps in the DNA Extraction Experiment?
- DNA is extracted by mashing/ lysing (breaking) cells. This can be done
using a soap solution that breaks the cell membranes. - Protease enzymes can be used to break down the proteins released when
cells burst. The proteins are not needed. - Cold ethanol is added to cause the DNA to precipitate. DNA is insoluble in ethanol so it cannot remain dissolved in the solution and forms a precipitate.
What are the steps in transcription?
- The DNA strand unwinds and hydrogen bonds break
- One strand will be used as the template and the RNA Polymerase binds to it at the non coding region.
- The RNA polymerase starts reading the bases and creates complementary bases for them.’
- After the RNA polymerase is finished that means the mRNA strand is created
5.Then the mRNA strand unbinds from the DNA
6, The DNA reforms back to its double helix formation and its hydrogen bonds reform - Lastly mRNA strand leaves nucleus through the pores and goes to the ribosome
What are the steps in translation?
- The mRNA binds onto the ribosome
2 . The first tRNA binds onto the triplet of bases carrying a specific amino acid - A second tRNA binds onto the next triplet holding a different amino acid
- The first tRNA unloads its amino acids onto the second one which forms a peptide bond.
- This process repeats until a protein is formed
- Which then folds into a 3D shape
What are the three outcomes from a mutation?
- Remains the same meaning the mutation had no affect
- Decrease , This is known as a harmful mutation.
3, Becomes more efficient , This is known as a
beneficial mutation
Name the disease that is caused by a mutation in the non coding region.
beta-thalassaemia
What are some symptoms of beta-thalassaemia?
Tiredness, weakness and shortness of breath
What are the three TYPES of mutation?
Substitution
insertion
deletion
What is the genotype of someone?
The alleles the person has
What is the phenotype of somone
The characteristic displayed by the alleles
What is a dominant allele
The allele that will always be expressed in the
phenotype e.g. D
What is a recessive allele
The allele that will only be expressed in the phenotype
if homozygous e.g. d
What is meant when someone has homozygous alleles
Both alleles are the same e.g. dd or DD
What is meant when someone has heterozygous alleles
One dominant and one recessive allele present e.g. Dd
What is meant by a allele
An alternative copy of a gene
What is meant by a chromosome
A structure containing DNA and protein that you inherit
from your parents. Contains many genes
