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Controlling Growth
1Q.
What determines a person’s height?
A person inherits information from their parents and this determines their height.
2Q.
What hormone controls growth in a person?
Human-growth hormone.
3Q.
4Q.
What are some causes of differences in people?

Environmental Factors ( diet, health, exercise)

Inheritance (genetic factors)
From whom an offspring inherits information from?
Their parents.
5Q.
What are chromosomes?
Thread like structure found in a nucleus containing genetic information.
6Q.
What is a gene made of?
DNA (blue print to make an individual)
7Q.
8Q.
9Q.
How does the difference in similar species of animals benefit the species?

Some rabbits are killed by myxomatosis while some are resistant and can survive.

Not all mosquitoes are killed by a pesticide called DDT.

Peacock with the best display of feathers is most likely to attract a partner.
How sometimes the difference in similar species of animals is not beneficial?

Pure white (Albino) giraffes do not survive long in the wild.

Antelopes that run slower than the herd do not survive.
What is the difference between a gene and a chromosome?
Gene: A heredity factor transferred from the parents to offspring and is found on
chromosomes.
Chromosome: Contains genetic information and is found in the nucleus.
10Q.
How do identical twins have exactly the same genes?
Identical twins have exactly the same genes as they come from the same zygote
(fertilized egg) which later multiplies into two zygotes.
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11Q.
Why do identical twins have the same genetic information?
Identical twins have the same genetic information because they come from the same
zygote (monozygotic) which contains one type of genetic information and when later the
zygote multiplies itself into two the genetic information also multiplies into two causing
the twins containing same information.
12Q.
13Q.
What does a classic twin study involves?

Twins raised in the same environment.

Identical twins have the same genes.

Non-identical twins share about 50% of themselves.

Similarity between a set of identical twins and a set of non-identical twins.
What is the difference between homologous and heterologous genes?
Homologous: A pair of two recessive genes indicated by two small letters.
Heterologous: A pair of genes in which one is dominant (indicated by a capital letter) and
the other is recessive.
14Q.
What does ‘inherited’ mean?
To receive the same information from the mother and father.
15Q.
What cells are gametes made up of?
Chromosomes.
16Q.
Where in the gametes are chromosomes found?
Nucleus.
17Q.
How many chromosomes are in a sperm cell?
46 Chromosomes.
18Q.
How many chromosomes are in an egg cell?
23.
19Q.
What is the pair of genes on chromosomes called?
Alleles.
20Q.
What happens when an egg is fertilized the male sperm, and what is it called?
The baby would have the complete set of information from father and mother which is
called inheritance.
21Q.
What is meant by fertilization?
The fusion of egg and sperm cell.
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22Q.
What are freckles in humans caused by? Explain.
They are caused by a brown pigment in the skin called melanin. Sometimes they are not
spread evenly throughout the skin.
23Q.
What can be analyzed by the scientists to find out if any parent is carrying any
genetic disease in a recessive form that they may pass on to their children?
By taking the DNA of the parents.
24Q.
What is meant by dominant and recessive genes? Explain.
Dominant Gene: The gene which is stronger and more expressive than the other gene.
Recessive Gene: A recessive gene is one that is not expressed unless there are two of
them, one from each parent.
25Q.
Why is the inheritance of a human eye-color complex?
26Q.
The inheritance is complex because if both the parents have the same eye color the child
is likely to get the same colored eyes but if the recessive gene of both parents is also the
same then the child can even get the color of the recessive gene of both parents but if the
recessive gene of both parents is different than the child would not develop either one of
the color of the recessive gene.
27Q.
Why do most plants brightly colored flowers?
So they can attract birds and bees to help spread their pollen.
28Q.
What kind of a plant is Japanese knotweed?
Ornamental
29Q.
What is the process called when plants produce new individuals without using
gametes?
A-sexual reproduction.
30Q.
What is the new individual called when plants produce new individuals without
using gametes?
Natural Clone.
31Q.
How many ways can plants reproduce? Explain in detail.
Sexual reproduction is production with gametes involving the ovary and the pollen to
form a new individual.
A-sexual reproduction is production without gametes involving as is identical to the
parent.
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32Q.
Which method of plant reproduction produces variety in the offspring?
Process of nuclear transfer.
33Q.
What is the process of nuclear transfer? Explain.
To take an egg cell and remove it’s nucleus and replace it with a nucleus from a normal
body cell.
34Q.
What is meant by artificial breeding or selective breeding?
Selective breeding is the process by which humans breed other animals and plants for particular
traits.
Selective breeding is the process by which humans breed other animals and plants for particular
traits.
35Q.
What features of the wolf are desirable to make a hunting dog?
36Q.
Why breeding pedigree dogs is an example of artificial selection?
37Q.
Which breed of wolf did the domestic dogs originate from?
Desert wolf, the woolly wolf, and gray wolf.
38Q.
How do the scientists know for sure the breed of wolf the domestic dogs originated
from?
DNA.
39Q.
What is the most common way of breeding pedigree dog?
Line breeding,
40Q.
What is meant by inbreeding?
To breed in closely related family, For example: Siblings.
41Q.
42Q.
What are some problems caused by inbreeding?

Blindness

Deafness

Heart Disease
What is the difference between inbreeding and line breeding?
Inbreeding is breeding between closely related relatives.
Line breeding is breeding between distantly related relatives.
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43Q.
What is a disadvantage of line breeding?
It takes several generations to get rid of unwanted features.
44Q.
What are some of the problems that arise as a result of inbreeding Dogs? List
45Q.

Blindness

Deafness

Heart Disease
Why is there a greater chance of recessive diseases being shown in inbreeding?
In breeding is between close relatives which means both carry the same recessive genes
and for the gene to express its self it is to be present in both the parents.
46Q.
Fill in the blanks.
1.
Another word that can be used to describe differences in people is variation
2.
Parents pass on information in the nucleus of their gametes to their offspring.
3.
Sometimes there are clear traits that run in the family such as shape of nose etc.
4.
DNA contains the ‘blueprint’ (recipe) to make an individual.
5.
Chromosomes carry genetic information in genes.
6.
Every cell in a human body except the gametes contains all the information needed to
make a new individual.
7.
DNA finger printing is used to identify criminals.
8.
Some differences in people are easily observable and so they can be easily recorded
9.
Any differences existing between identical twins are due to the effect of the
environmental factors.
10.
Genotype shows all types of genes present for a particular character or features.
11.
Phenotype is physical appearance.
12. Only gonads produce gametes.
13. The gender of a human embryo is an
feature.
14. It is gene that carries the information that determines what sex we are and what we look
like.
15. There are two genes for each feature in a cell from each parent.
16.
Egg cell contains one set of genes/chromosomes whereas Sperm cell contains one set of
genes/chromosomes.