Download L1 Science (90188) 2007

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90188
Level 1 Science, 2007
90188 Describe aspects of biology
Credits: Five
You should answer ALL the questions in this booklet.
For Assessor’s use only
Achievement
Describe aspects of biology.
Achievement Criteria
Achievement with Merit
Explain aspects of biology.
Achievement with
Excellence
Discuss aspects of biology.
Overall Level of Performance
© New Zealand Qualifications Authority, 2007
All rights reserved. No part of this publication may be reproduced by any means without the prior permission of the
New Zealand Qualifications Authority.
You are advised to spend 40 minutes answering the questions in this booklet.
QUESTION ONE
Compost is formed by the action of saprophytic micro-organisms producing carbon dioxide, water, heat,
and humus (the end-product).
(a) Describe the term saprophytic.
A saprophytic is a plant living on dead or decaying organic matter
An example of a compost heap:
(b) Explain why good air flow is necessary for the decomposition of the organic matter.
The good air flow gives a good source of oxygen so the saprophytic micro-organisms can stay alive and
keep producing carbon dioxide, water, heat, and humus
The graph shows the temperature of the compost over a few days.
The increase in temperature is caused by the action of bacteria and fungi on the organic matter.
(c)
From day 8 there is a marked drop in the temperature of the compost heap.
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Explain why this occurs.
Because the saprophytic is in peak which caused the dramatic high in heat but when it went out of peak the
temperature fell which caused the temperature to drop
QUESTION TWO
(a)
Describe how a fungus gains its nutrition. The fungus gets its nutrition through its hyphae. The
hyphae are the feeding source for the fungi.
(b)
Discuss how hyphae and sporangia aid the spread of a fungus. You should consider their function and
role in the spread.
Fungi have spores in the sporangia which is the reproductive system in the fungi when the spores are
released it spreads the spores which soon turn in fungus. The hyphae is the feeding source for the
fungus the hyphae digs in the food so it can be absorbed by the fungus
QUESTION THREE
(a)
Below is a general diagram of a virus.
On the lines provided, name the structures A and B.
Protein Coat
DNA
(b)
The life processes of viruses differ from bacteria.
Compare and contrast the life processes of viruses and bacteria.
Viruses are considerably smaller then bacteria. Instead of being a living cell able to undergo a life cycle on
their own (bacteria can do this), they must take over the cell processes of another cell in order to
reproduce.
Viruses and bacteria are similar in that they both need a suitable environment to survive. Bacteria and
viruses are both pathogenic (disease causing) to humans.
Bacteria are killed by antibiotics. While viruses are not.
QUESTION FOUR
(a) Describe the relationship between a chromosome and a gene.
A gene is a string of DNA information that carries a trait from an organism to its offspring. A
chromosome is a string of DNA containing several genes.
There are 23 pairs of chromosomes in each human body cell.
One of these pairs of chromosomes is the sex chromosomes.
(b)
Give the genotype for the sex chromosomes of a human female. The female gametes or eggs however,
L1 Science 2007, 90188 – page 3 of 5
contain only the X sex chromosome and are homogametic.
(c)
Discuss why sex cells have 23 chromosomes, where as body cells have 46. Refer to the cell division
processes involved. Because the when the zygote is conceived it has 23 chromosomes from each
parent. If a zygote had 46 chromosomes then the zygote will be counted as abnormal.
QUESTION FIVE
In some breeds of rabbit, a plain coat color is called solid; a blotchy coat color is called broken. Broken coat
(B) is dominant to solid coat (b).
A solid-coated rabbit is crossed with a heterozygous broken-coated rabbit.
(a)
Give the genotype of the solid-coated rabbit.
(b)
Complete the Punnett square for this cross.
bb
b
b
B
Bb
Bb
B
Bb
Bb
BB
(c)
Use the information in the Punnett square to determine the proportion of the offspring that are able to
pass on the solid coat trait to their own offspring. Broken coat
(d) Explain your answer to question (c) above.
Since the broken coat is more dominate than the solid coat the offspring will be a broken coat.
(e)
Define the term homozygous. A homozygous refers to having identical alleles for a single trait.
(f)
A breeder buys a rabbit with the broken coat trait.
Discuss the process that could be used to identify whether this rabbit is homozygous or heterozygous
for broken coat.
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Keep on interbreeding the rabbit and see if the broken coat comes out in the Leveret is it does then it’s a
homozygous if it doesn’t than it’s a heterozygous
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