B1.2 What happens in Cells Flashcards
State the role of DNA in the body
DNA is the substance that contains all the instructions that determine your characteristics
What is a chromosome? How many do humans have?
A long molecule of DNA
46
§What are genes?
Short sections of DNA that code for a characteristic, such as eye colour
How many strands is DNA made up of? What shape is DNA using the strands
2 strands
The 2 strands are twisted together to form a double helix
What are the 4 base pairings? Which base links with the other?
Adenine, Thymine, Guanine, Cytosine
Adenine links with Thymine : Guanine links with Cytosine
What is each nucleotide made up of?
sugar molecules (deoxyribose)
Phosphate
1 base
Why is DNA a polymer?
The small units of nucleotides are joined together
What are enzymes made of?
Protein
Enzymes are biological catalysts. What does this mean?
Biological catalysts speed up a reaction without being used up themselves.Oncea reaction is finished they can be used to catalyse the same type of reaction again.
What do enzymes do? (2)
Build larger molecules from smaller ones, such as protein synthesis.
Break down large molecules into smaller ones, such as in digestion.
What is an ‘active site’
An active site is part of an enzyme that binds to the substrate. It has a specific shape which is formed by the way its amino acids are folded togther within the protein.
Can enzymes bind to all molecules? Explain why/why not?
No as enzymes are highly specific.
This means they can only bind to one type of substrate molecule.
The substrate must fit exactly into the active site.If it does not, the molecule cannot bind.
What is formed when a substrate binds to an enzyme?
enzyme-substrate complex
What 2 factors affect enzymes?
pH and temperature
How does temperature affect enzyme reactions?
Higher temperature will increase the movement of enzyme and substrate molecules which will collide more often allowing the enzyme to react quicker.
If temperatures are too high then an enzyme will denature (stop working)
how does pH affect enzyme reactions?
Different enzymes work quicker in more acidic or more alkaline parts of the body
how does substrate or enzyme concentration affect enzyme reactions?
The higher the substrate concentration is, the faster the rate of reaction.
At a certain concentration, all enzyme molecules, are bound to substrate molecules and the rate of reaction will be at its maximum.
Any further increase in the number of substrate molecules will not increase the rate of the reaction as there are no enzymes for them to bind to
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| ___ -What is this direct drop
| / |
| / |
| / |
|/______________
Substarate used up
Rate | What does this point mean?
Of | /
Reaction | ___________
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| /
|/_______________
Substarte concentration
Point of saturation
Place in size order: gene, chromosome, genome, DNA, nucleus, cell, nucleotide
Nucleotide (smallest)
Gene
DNA
Chromosome
Genome
Nucleus
Cell (largest)
What is DNA?
DNA is deoxyribose nucleic acid, the genetic material found within the nucleus of every one of your cells.
Name the protein that DNA coils around in the formation of a chromosome
Histone proteins
Who produced the first ever photograph of DNA, ‘photo 51’, that led to the discover of DNA’s structure.
Rosalind Franklin
What is the name of the weak bonds formed between bases of opposing strands of DNA?
Hydrogen bonds
