Transcript File - Year 11 Revision

B2 Topic 1 Revision
Slides 2-12 GM - these activities are designed to
take a whole lesson. Make sure you stick to the
timings given in the notes that go with each slide.
Slides 13- 19 Graphs, data and enzymes - these
activities should take 30mins.
Slides 20-29 Mitosis & Meiosis, protein synthesis
and DNA replication - this content recap and exam
questions should take 30-40mins
Slide 30 - Revision Quiz, covers lots of bits and
pieces, 15 questions, will probably take 20-25mins
Science-y bit - step by
step guide to GM
(worth 4 marks)
Unpicking the Question
At least 6
statements
about science in
your answer
1. This question is about genetic modification
Explain how bacteria can be genetically modified to
produce human insulin.
Suggest benefits of using human insulin rather than
insulin extracted from animals.
(6 marks)
2 reasons why it is used (think science proteins and their shape)
(The quality of written communication will be assessed
in your answer to this question)
Logical order, uses key words, good spelling, good punctuation
The Science - Genetic Engineering
1. Isolate the desired
gene using enzymes
4. Transfer vector containing
gene into bacteria
2. Replicate the gene
3. Put gene into vector
(eg a plasmid)
5. Bacteria will now produce the
protein from the desired gene
Decide: which two of the following are
relevant to the question being asked?
Suggest benefits of using human insulin rather
than insulin extracted from animals.
Using human insulin is better because vegetarians will be able to
use it too
Human insulin will be an exact match for the insulin needed by
the diabetic person, animal insulin is a slightly different shaped
protein
It isn’t right to kill pigs to collect insulin from them
The immune system might reject or attack the pig insulin as the
protein is a different shape to human insulin
Explain how bacteria can be modified to produce human insulin.
Suggest benefits of using human insulin rather than insulin extracted
from animals (6 marks QWC).
Vocab
Diagrams
2 mins
3 mins
Bullet points
4 mins
Paragraph
5 mins
Swap books and mark someone else’s answer.
Give them a WWW and EBI.
How many marks did they get for the Science (max 6)?
Now mark the quality of their writing using the
criteria on the left.
Did they use the key words?
Is it logical?
Are all the spellings correct?
Good use of punctuation?
Give them a WWW and EBI for the quality of
their answer
Now improve your answer!
3 minutes
Mark your own work this time.
How did you do compared to
your first attempt?
Now take what you know and apply it!
Organisms can be genetically engineered to make them more
useful to humans.
Suggest how wheat could be genetically engineered to allow it to
grow in wet, marshy land (6 marks QWC)
Mark scheme - mark your own
this time
Identify a gene that allows a plant to grow in wet/marshy areas.
Isolate/extract/cut out the gene with a restriction
(endonuclease)/enzyme
Replicate the gene
Insert desired gene into a vector (eg plasmid/virus)
Transfer vector/plasmid containing desired gene into wheat/crop
Crop plant will now produce/synthesis protein that allows it to
grow in wet/marshy conditions
Give yourself a WWW and EBI
The Science - Genetic Engineering
1. Isolate the desired
gene using enzymes
4. Transfer vector containing
gene into bacteria
2. Replicate the gene
3. Put gene into vector
(eg a plasmid)
5. Bacteria will now produce the
protein from the desired gene
2 - Daunting Data and Grim Graphs
Why is the volume
at it’s highest here?
Tell me what you see, using
numbers from the graph
(ii) Describe the effect of
temperature on the volume of juice
produced between 10°C and 40°C (2)
(iv) Use the lock and key hypothesis
to help you explain the activity of
pectinase in juice production
between 10°C and 70°C (6)
What is
happening to the
enzymes here?
What is happening
Use Science to tell me why
to the enzymes
you see this pattern
here?
Student Model Answers
Student A
a) As the temperature increases, the volume of juice produced increases.
b) Between 10oC and 40oC the enzymes are gaining kinetic energy meaning they are moving
around faster and will form more enzyme-substrate complexes. At 70oC the enzymes have
been denatured and don’t work anymore.
Student B
a) The volume of juice produced increases as the temperature increases. At 10oC 0.6cm3 is
produced and at 40oC 2.7cm3 of juice is produced.
b) The enzyme has a specific active site and the substrates will only fit into the active site if it
hasn’t been denatured by getting too hot. On the graph it denatures when it goes down.
Before that, the enzyme works faster as it gets hotter.
Student C
a) The graph goes up and then goes down again. It goes up between 10oC and 40oC from 0.6 to
2.7.
b) The enzyme works faster as the temperature gets hotter. From 10oC to 40oC the enzymes
gain kinetic energy so collide with each other more often, forming more enzyme-substrate
complexes. The substrate fits into the active site, but when it gets too hot the enzyme
denatures and the active site changes shape meaning that no more enzymes-substrate
complexes will be formed. The graphs dips down after 50oC when the enzyme denatures.
Mark the student
answers and give
each a WWW
and EBI
Use what you have learnt!
Now write your own response to the questions
(ii) Describe the effect of
temperature on the volume of juice
produced between 10°C and 40°C (2)
(iv) Use the lock and key hypothesis
to help you explain the activity of
pectinase in juice production
between 10°C and 70°C (6)
Now mark
your own
answers
3 - Genes, Protein Synthesis, DNA
Replication, Mitosis and Meiosis,
Cloning
Protein
Synthesis
Ribosome
Transcription
Translation
DNA
Replication
Before mitosis and meiosis
Semi-conservative
1. Enzyme unzips DNA
2. Free complementary bases line
up with exposed bases on DNA
3. A different enzyme zips them
together
4. Two identical strands of DNA
formed
Mitosis or Meiosis?
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Daughter cells are genetically identical to parent cells
Produces cells with only half the number of chromosomes
Produces gametes
The cell goes through one division
Produces 4 daughter cells that are genetically different
Produces diploid cells
Is a process within the cell cycle
Occurs in the ovaries and testes
The cell goes through two divisions
Is used in Asexual reproduction
Describe and explain the differences in chromosome
number between the daughter cells produced by
Mitosis and Meiosis (6 marks)
Mitosis
1 division/2 daughter cells
Chromosome number maintained
Daughter cells contain 2n/23 pairs/46 chromosomes
For growth and repair/ asexual reproduction
Meiosis
2 divisions/ 4 daughter cells
Chromosome number halved
Daughter cells contain n/23 individual chromosomes
For making gametes/egg cells/sperm cells
Chromosome number restored at fertilisation
Cloning - put these statements
into the correct order
A Enucleate the egg cell
B The diploid nucleus inside the egg cell starts dividing by mitosis
C Insert the diploid donor nucleus into the enucleated egg cell
D Implant the growing embryo into womb of surrogate
E Collect an egg cell from the egg cell donor
F Diploid nucleus is removed from body cell of organism you want to clone
G Stimulate the diploid nucleus using an electric shock or chemicals
A clone is born!
Answer: F, E, A, C, G, B, D
Q1.
(a) The diagram shows the mass of DNA (m), before, during and after cell division in
one cell.
(i) Name the type of cell division taking place in this cell. (1)
(ii) Complete the sentence: A gene is a section of DNA that codes for ……………………(1)
(b) Mutations can cause genetic disorders in humans. Phenylketonuria (PKU) is a
genetic disorder caused by a gene mutation. People with PKU produce an inactive
enzyme.
The normal base sequence and the mutated base sequence which can cause PKU are
shown below.
normal base sequence
....... C T C G G C C C T .......
mutated base sequence ....... C T T G G C C C T .......
(i) Describe how the changes that have occurred in the mutated base sequence
produce an inactive enzyme (2)
(ii) Explain how the mutated base sequence will result in an inactive enzyme being
produced during protein synthesis. (6)
(c) Explain how the shape of an enzyme can make it inactive. (2)
Mark scheme
a) i) Meiosis
ii) C
b) i) A description including any two from the following points
• change in a base from C to T (1)
• (causes) change in one {codon/triplet} of bases (1)
• results in a different amino acid (1)
b) ii) next page
c) An explanation linking the following points
• active site {different / blocked / changed} (1)
• substrate cannot bind /eq (1)
An explanation linking some of the following points
• enzymes are proteins
• mutation in DNA will result in different mRNA strand
• during transcription
• mRNA leaves the nucleus through the nuclear pore
• the attachment of mRNA at the ribosomes
• involvement of tRNA and amino acids
• at the ribosome
• which is translation
• amino acid chain/peptide sequence altered
• different protein formed/protein not folded correctly
(6)
QWC 5 - 6 marks
 the response is likely to indicate the type of mutation and link this to a change of
codon/protein
 the response will show good evidence of understanding that an incorrect mRNA
molecule is formed and translation by tRNA will result in an incorrect amino acid
being incorporated into the protein chain
 the answer communicates ideas clearly and coherently uses a range of scientific
terminology accurately
 spelling, punctuation and grammar are used with few errors
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Revision
Quiz
Name two of the scientists involved in the discovery of DNA
How many cells are produced as a result of meiosis
By how much can an electron microscope magnify a specimen?
What bonds hold the two complementary strands of DNA together?
What does the word ‘diploid’ mean?
In cloning, what is used to stimulate the egg cell to start dividing?
Give one feature of a bacterial cell that isn’t present in animal or plant cells.
What is the function of the mitochondria?
By how much can a light microscopes magnify a specimen?
What do the letters A, T, C and G stand for in DNA?
A specimen appears 15mm under a light microscope at a magnification of
1000, what is its real length?
What is a gene?
Name two organisms that have been genetically engineered to benefit humans
Where do the majority of stem cells come from that are used in stem cell
research?
What happens when an enzyme becomes denatured?
1.
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15.
Watson, Crick, Rosalind, Franklin
Four
2 000 000x
Hydrogen bonds
Two of each chromosome/chromosomes in pairs
Body cell nuclus donor
Plasmid/chromosomal DNA, cell wall not made of cellulose, mesosome,
Pilli (not flagella; sperm cells have flagella so be careful with this one)
Release energy OR produce/make ATP (NOT make energy!)
1500x
Adenine, thymine, cytosine, guanine
0.015mm (remember the units!)
Section of DNA that codes fro a protein
Bacteria to produce insulin, golden rice, herbicide resistant crop plants
Embryos left over from IVF
The active site changes SHAPE