B1.2 Flashcards
State the role of DNA in the body
DNA is a biological polymer made from nucleotide monomers
DNA is the substance that contains all the instructions that determine your characteristics
Where is DNA found
In the nucleus
Each long molecule is a ….
… Chromosome
What is a chromosome
Long molecule of tightly coiled DNA
How many pairs or chromosomes do humans have
23 (46 chromosomes)
What is a gene
A short section of DNA found upon a chromosome which codes for a specific protein
Order it
Nucleotide (smallest)
Gene
DNA
Chromosome
Genome
Nucleus
Cell (largest)
What are nucleotides?
The building blocks of DNA
Small units that make up up dna
What does a nucleotide consist of?
- Phosphate backbone
- Deoxyribose sugar
- Base.
What is the structure of DNA
Double helix (2 strands joined together by bases)
What are the bases and their complimentary pairing?
A -> T
C -> G
What is a polymer
polymers are large molecules (like DNA) made by bonding a series of building blocks
What is the name of the weak bonds formed between bases of opposing strands of DNA?
Hydrogen bonds
Name the 2 main stages of protein synthesis
Transcription (1) and translation (2)
What is mRNA
mRNA is a singular strand of DNA that contains bases and carries those into the cytoplasm
What is transcription
Transcription is when the 2 strands of DNA unzips and one strand is used as a template for mRNA to use and the complimentary bases are copied onto the mRNA. And as DNA is too large to send out the nucleus. mRNA travels out of the nucleus into the cytoplasm.
What are proteins made from.
Amino acid chains
That is translation
Translation is when the mRNA attaches to the ribosome and the ribosome reads the nucleotides in groups of threes called codons then tRNA attaches the anticodon (the complimentary base pairings to the mRNA) to the amino acid. A chain of amino acids are formed. A protein is formed
What is rna
A singular strand of dna
What are enzymes
Enzymes are biological catalysts - they speed up a reaction without being used up. They are made out of proteins
What are example of what enzymes do?
• build larger molecules from small ones, such as in protein synthesis
• break down large molecules into smaller ones, such as in digestion.
What is the name of the molecule the enzyme binds to?
Substrate
What is an active site?
The area of the enzyme that attaches to the molecule it is trying to break down
What happens when an enzyme is trying to break down a substrate?
The substrate (which has a specific shape) binds to the active site (has a specific shape) which is part of the enzyme. The substrate fits inside the enzyme to form an enzyme-substrate complex
What is formed when a substrate binds to an enzyme
An enzyme-substrate complex
Can enzymes bind to any substrate?
No, enzymes are highly specific. They can only bind to one type of enzyme molecule. (Lock and key)
What happens in the reaction where enzymes build larger molecules from smaller ones?
- The substrate molecules fit into the enzymes active site
- The bond forms
- Product is released
- Enzyme is ready to catalyse another reaction
What happens in the reaction where enzymes breakdown large molecules into smaller ones?
- The large Substrate molecule fits into the active site
- The bond breaks
- The 2 smaller products are released
- Enzyme ready to catalyse another substrate
What factors affect enzyme activity?
- Temperature
- pH
- Enzyme and substrate concentration
How does the temperature affect the reaction?
- the higher the temperature, the faster the reaction
- the optimum temperature(the highest before denaturing) is when it works best
- if the temperature gets too high, the enzyme will denature meaning the amino acids chains will unravel changing the shape of the active site.
- the substrate can no longer bind to the active site so the rate of reaction decreases. Once all enzyme molecules are denatured the reaction stops
How does pH affect the reaction?
- if the pH is changed, it will affect the interactions between the amino acids in the chain
- this makes the enzyme unfold changing the shape of the active site (it has denatured)
- each enzyme has an optimum pH
How does the concentrations of the enzyme and substrate affect the reaction?
- the higher the substrate concentration is, the faster the reaction
- the higher the enzyme concentration the faster the reaction
- but at a certain point the rate of reaction is at its MAXIMUM (point of saturation). All of the substrate molecules are connected to the enzyme molecules (there are none left to connect).
- any further increase of the substrate molecules will not increase the rate of reaction because there are no enzyme molecules for them to connect to - same with the enzymes (once all the substrate molecules are used up, the reaction will stop)
