SCIENCE B2 REVISION
Flash cards & more!
PLEASE NOTE THAT THIS PRESENTATION DOESN’T HAVE EVERYTHING IN B2! Some topics are left out.
DNA
Located in the nucleus for plant/animal cells. Found in chromosomal DNA and plasmid DNA for bacterial cells.
Genes are just sections of chromosomes which code for specific proteins.
DNA has a double helix structure.
DNA Nucleotide / Mono nucleotide
Phosphate group
Deoxyribose sugar / pentose sugar
Base
Has 5 carbons.
Click me!
State two ways in which the structure of this yeast cell differs from the structure of a bacterial cell. (2 marks)
Make sure you read the question well. In this one, we can only list two points.
Model Answer:
“A bacterial cell generally has a flagellum and it doesn’t have a nucleus like a yeast cell.”
You don’t need to write much, since it’s only for two marks and it’s asking you to plainly state two points.
1
1
CHROMOSOMES DNA
More specific, allows particular traits
Strands of chromosomes
Proteins make up most of your body.
Except bone; that is made out of calcium.
What does the term “magnification” mean?
The distance of zooming in on an
object
High magnification
No magnification
What is the resolution?
The clarity and quality of an image from a microscope
More things on DNA that you should know…
This is how a DNA Nucleotide/mono nucleotide
is drawn.
Err, mayor… what’s that?
Ohh, right! How
interesting, mayor!
What’s the maximum magnification of a modern telescope?
2,000,000 times
How do you calculate the actual length of an object?
Length of magnified object
Magnification
Example = length of magnified object is 87mm, and the magnification is 2100.
87/2100 = 0.042
How do you calculate the length of a magnified object?
Length of object
Magnification
Example = length of object is 87mm, and the magnification is 2100.
87*2100 = 170100
*
What is a characteristic of genetic engineering?
It produces a unique set of
genes.
What does enucleation mean?
Removal of a nucleus.
What’s the first stage of copying a DNA strand?
Translation
Which four bases are present in mRNA?
ACGU
Where’s mRNA made?
Nucleus
Where does the mRNA get made?
Ribosomes
Where does the mRNA move in order to be read?
Ribosomes
What’s the name of the long chain of amino acids that’s formed?
Polypeptide
What’s another name for enzymes?
Biological catalysts
BasesI’m all about that base, ‘bout that
base, no (pentose) sugar…
You must memorize four bases:
• Adenine• Thymine• Guanine• Cytosine
The bases all pair up to a particular base. (OTP!!!)
A x TC x G
A joins up with T, C joins up with G. You must remember this. This is the case for DNA, but not RNA (if RNA isn’t in this presentation, you’re on
your own, bud).