B3 Flashcards
What is DNA
DNA is two strands coiled together to form a double helix. Each of the strands contains chemicals called bases and there are for different types. There are cross links between the strands to for pairs of bases..
Each gene has coded…..
genetic information
What are chromosomes?
They are long, coiled up molecules of DNA - they are divided into sections called genes
What do genes contain? What do they code for?
The genetic code consist of different sequences of base pairs in a particular length of DNA. Each gene codes for a particular protein
Where are the proteins made and why is a copy of the gene needed?
The Proteins are made in the cytoplasm. A copy of the gene is needed as the gene cannot leave the nucleus; they are in chromosomes
What are the four bases of DNA?
A, T, G, C
Describe complementary base pairing
A always pairs with T, and G always pairs with C
How does protein structure determine the DNA base code?
The base sequence determines the amino acids and each amino acid is coded by a sequence of base triplets
How does the code needed to produce a protein carried?
The code is carried from the DNA to the ribosomes by a molecule called mRNA
How does DNA control cell functions?
It control the production of proteins, some of these are enzymes.
How did Watson and Crick use data from other scientists to build the model of DNA?
W and C used x-ray data showing there were two chains wound in a helix. They also obtained data indicating the bases occurred in pairs.
Why are new discoveries not accepted or rewarded immediately?
They need to be repeated and tested by other scientists to test the work; they need verify it
What are proteins made of?
They are made from long chains of amino acids
What is collagen?
Collagen - structural protein makes up structure of body.
What is an enzyme?
They are biological catalysts as they catalyse chemical reactions occurring in living cells e.g respiration, photosynthesis, protein synthesis. They also have high specificity in for the substrate molecule
Describe the lock and key mechanism
The substrate molecule fits into the active site. This is called specificity as the substrate has to be the right shape, like a key
What will change the rate of the reaction in an enzyme catalysed reaction?
pH and temperature change away from optimum
How is enzyme activity affected by temperature and pH?
Low temperatures mean lower collision rates
Extremely high pH and temperature means enzymes denature
Denaturing is irreversible and damages enzymes (active site)
What is temperature coefficient? (Q10)
Rate at higher temperature / rate a lower temperature
What is insulin?
Hormone made in pancreas. Traces in blood stem to target irfan. It regulates blood sugar level.