Ch.4.5

Question 1

Traits are _________________________________________________________________________________.

Answer 1

the features each generation inherits from their parents

Question 2

Heredity is _________________________________________________________, _____________________________________________.

Answer 2

the passing of traits from parents to the next generation, as a result of the transmission of genetic information

Question 3

How do parents pass their traits to the next generation?
Through the ___________________ of ________________ _____________________. Traits are determined by the ___________ in the ________________ of cells. They carry _______________ ___________________. The _______________ formed after fertilisation receives _____________ of its genetic information from the ________________ and _____________ from the _______________. Therefore, a child inherits traits from _________ ____________.

Answer 3

transmission, genetic information, DNA, nucleus, genetic information, zygote, half, father, half, mother, both parents

Question 4

The _____________________________________________________________________________________ can be shown in a ‘_____________ ___________ ___________’ (aka _________________).

Answer 4

passing of a particular trait through several generations in a family, genetic traits tree, pedigree

Question 5

By analysing this diagram, we can ___________________________________________________________________________________. We may also ____________ ___________ _____________ the trait will ___________ ________ _________ _____________ _______________.

Answer 5

trace the passing of the trait through each generation, predict how likely, occur in the next generation

Question 6

In general, in a pedigree, squares symbolise ____________ and circles symbolise ________________. Children are arranged in the ____________ of ______________ from _____________ to _____________.

Answer 6

males, females, order, birth, left, right

Question 7

Variations are _________________________________________________.

Answer 7

the differences in features among individuals of a species

Question 8

Two types of variations:
1.
2.

Answer 8

Continuous, discontinuous

Question 9

Continuous variation shows a _________________ _______________ of ____________________. They are usually presented in ________________ and have a ______________ ______________ between two differences. Eg _______________, ______________ ______________, _____________ ______________ and ___________________ __________________ (_____). We can draw a _______________________ to present the data of a continuous variation with a title starting with ‘________________ of…’

Answer 9

continuous range, differences, numbers, middle point, height, body mass, hand span, intelligence quotient (IQ), histogram, distribution

Question 10

Discontinuous variation shows ____________ __________ ___________________. Eg __________________________, _____________________________, ________________________ and ______________. We can draw a __________ ______________ to present the data of a discontinuous variation.

Answer 10

clear cut differences, with or without earlobe, curved or straight thumb, blood group, genders, bar chart

Question 11

Some variations are determined by ________________ while some are determined by the ________________. Besides, there are variations that are determined by ________________ ________________.

Answer 11

Heredity, environment, both factors

Question 12

Variations determined by heredity are called ________________ ________________ (or ________________ ________________). These variations ________________ __________ __________________ as they are ____________ _______________ __________ ________________ ______________________.

Answer 12

inherited variations, genetic variations, cannot be changed, not affected by the environment

Question 13

-
-

Answer 13

natural hair colour, natural eye colour, most discontinuous variations

Question 14

Variations determined by the environment are called __________________ ________________.

Answer 14

environmental variations

Question 15

Examples of environmental variations:

• ________________ rabbit
• ________________ colour around the __________, _____________, __________ and ________________ changes with the environment
• ________________
• its ________________ varies depending on the ________________ of the ________________ which it grows

Answer 15

Himalayan, dark, ears, nose, legs, tail

Colour, conditions, soil

Question 16

Examples of variations caused by both environment and heredity: ________________ ________________
The ________________ ________________ we’ve learnt are usually determined by both heredity and the environment.

Answer 16

skin colour, continuous variations

Question 17

In rare cases where __________ embryos develop at the ______________ time, the ___________ babies born from a ________________ pregnancy are called ________________.

Answer 17

two, same, two, single, twins

Question 18

Identical twins result from a ________________ ________________. The ________________ formed after fertilisation splits into ________________ ________________ and each one develops into a baby. The two babies have the ________________ ________________ ________________. They are of the ________________ ________________ and ________________ ________________ ________________ ________________.

Answer 18

single zygote, zygote, two cells, same genetic materials, same gender, look like each other

Question 19

Non-identical twins result from ___________ _________ that are released from the ________________ at the ________________ ________________ and both are ________________.
The two babies have ________________ ________________ ________________ as they are developed from two different ________________ and ____________.
They are just like babies of ___________ ________________ ___________________ and may be of the ________________ ________________ or ________________ ________________. They may ________________ ________________ from each other.

Answer 19

two ova, ovary, same time, fertilised
different genetic materials, ova, sperm
two separate pregnancies, same gender, different gender, look different

Question 20

Identical twins have the same genetic materials. However, ____________________________________________________________________________________________ when they grow up. Variations between identical twins are due to ________________ in their ________________ ________________ and ____________________.
Eg their _______________ and ______________ ______________ may be different if they have different ____________________ and ____________________ ____________________, and their ____________________ ____________________ may be different if they have different ________________ of ____________________ to ____________________.

Answer 20

identical twins can still have variations in their features
difference, living habits, environments
height, body mass, exercises, eating habits, skin colours, levels, exposure, sunlight

Question 21

A DNA consists _____________ _______________. On the strands there are _____________ different kinds of ______________: _____, _____, _____, and ____ for short.

Answer 21

two strands, four, bases, A, T, C, G

Question 22

The __________ on the two ____________ pair up in a way that makes DNA a ____________________ ______________: _____+_____ and _____+_____. The way how they pair up is known as _______________________ ______________ _______________. If the sequence of bases on one strand is known, the ______________ of _________________ ______________ on the other strand can _____________ __________ ______________.

Answer 22

bases, strands, double helix, A,T, C, G, complementary base pairing, sequence, complementary bases, also be known

Question 23

The ______________ of _____________ on DNA acts as ______________ ______________. It encodes ‘______________’ that determine our ______________.

Answer 23

sequence, bases, genetic code, messages, traits

Question 24

Every ______________ bases of a DNA strand encode __________ ‘message’, so it is called a ______________ ______________. These ‘messages’ are actually __________________ for the ____________ to _______________________________________________________________.

Answer 24

three, one, triplet code, instructions, cells, make different types of proteins in the body

Question 25

By ___________________________________________________________________, DNA can determine our ______________ ______________, that is, ______________ _________________ ___________ ___________ ______________.

Answer 25

controlling the types of proteins a cell makes, body features, traits inherited from our parents