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grade-8-mock

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Name: _______________________________________________
U2 Science Summative
FORM C
Date: Wednesday 11 December 2019
Time: 45 minutes
Total marks available:
Total marks achieved: ______
Minas El Alami
Questions
Q1.
Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a
human.
Figure 19
(i) These cells are animal cells.
Animal cells do not have
(1)
A
B
C
D
cytoplasm
a cell membrane
a cell wall
mitochondria
(ii) state 3 differences between animal cell and bacterial cell
(3)
(iii) state 2 differences between animal and plant cell.
(2)
Q2.
Figure 1 shows a pea plant with flowers.
The seeds produced by this pea plant can be round or wrinkled.
The allele for round seeds (R) is dominant to the allele for wrinkled seeds (r).
(i) A homozygous dominant round seeded plant was crossed with a homozygous recessive wrinkled
seeded plant.
Complete the Punnett square to show the genotypes of the offspring.
(1)
(ii) State the percentage of the offspring that will produce round seeds.
(1)
percentage = ........................................................... %
(iii) Which scientist discovered the basis of genetic inheritance by crossing pea plants?
(1)
A
Charles Darwin
B
Alfred Wallace
C
Louis Leakey
D
Gregor Mendel
(iv) state the difference between a chromosome and a DNA
(v) state the difference between a gene and an allele
Q3.
Figure 2 shows part of a DNA molecule.
Figure 2
DNA can be extracted from fruit.
Describe how cells are broken down to release DNA.
(2)
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Q4.
Colistin is an antibiotic used to treat infections in the bloodstream.
Some bacteria are resistant to Colistin.
Explain 3 ways how these bacteria have become resistant to Colistin.
(4)
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Q5.
James Watson and Francis Crick built a model that showed that DNA has a double helix structure.
(i) Which statement about DNA is correct?
(1)
A
each pair of bases is joined by hydrogen bonds
B
phosphate groups are joined by hydrogen bonds
C
nucleotides consist of a sugar and a phosphate group only
D
bases are joined to phosphate molecules
(ii) Figure 13 shows the percentage of each base in human DNA.
Describe how this data provides evidence for base pairing in DNA.
(2)
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Q6.
Figure 2 shows part of a DNA molecule.
Figure 2
(a) (i) What is the shape of a DNA molecule?
(1)
A
B
C
single helix
double helix
complementary helix
D
triple helix
(ii) Which molecules are present in the DNA backbone?
(1)
A
B
C
D
sugars and phosphates
amino acids and bases
sugars and bases
amino acids and phosphates
(iii) State the type of bond that joins the bases together in the DNA molecule.
(1)
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Q7.
Mitochondria cannot be seen with a light microscope.
What is the function of mitochondria in a plant cell?
(1)
A
respiration
B
make proteins
C
photosynthesis
D
store water
Q8.
Antibiotics can be used to treat diseases.
Antibiotics kill
(1)
A
B
C
D
antibodies
antigens
bacteria
viruses
Q9.
Figure 10 shows a plant cell as seen under a light microscope.
Draw this plant cell in the space below.
Label three parts of this cell.
Q10.
Gregor Mendel investigated genetic inheritance using pea plants.
Figure 3 shows some of the equipment used in this investigation.
Figure 3
In an investigation, Mendel crossed pea plants that produced yellow seeds (AA) with pea plants that
produced green seeds (aa).
The dominant allele is shown as A.
The Punnett square shows the genotypes of the offspring from this cross.
Explain a conclusion that can be made from the results of this cross.
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Explain the difference between a genotype and a phenotype
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