Ch.4.5 Flashcards
Traits are _________________________________________________________________________________.
the features each generation inherits from their parents
Heredity is _________________________________________________________, _____________________________________________.
the passing of traits from parents to the next generation, as a result of the transmission of genetic information
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 _________ ____________.
transmission, genetic information, DNA, nucleus, genetic information, zygote, half, father, half, mother, both parents
The _____________________________________________________________________________________ can be shown in a ‘_____________ ___________ ___________’ (aka _________________).
passing of a particular trait through several generations in a family, genetic traits tree, pedigree
By analysing this diagram, we can ___________________________________________________________________________________. We may also ____________ ___________ _____________ the trait will ___________ ________ _________ _____________ _______________.
trace the passing of the trait through each generation, predict how likely, occur in the next generation
In general, in a pedigree, squares symbolise ____________ and circles symbolise ________________. Children are arranged in the ____________ of ______________ from _____________ to _____________.
males, females, order, birth, left, right
Variations are _________________________________________________.
the differences in features among individuals of a species
Two types of variations:
1.
2.
Continuous, discontinuous
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…’
continuous range, differences, numbers, middle point, height, body mass, hand span, intelligence quotient (IQ), histogram, distribution
Discontinuous variation shows ____________ __________ ___________________. Eg __________________________, _____________________________, ________________________ and ______________. We can draw a __________ ______________ to present the data of a discontinuous variation.
clear cut differences, with or without earlobe, curved or straight thumb, blood group, genders, bar chart
Some variations are determined by ________________ while some are determined by the ________________. Besides, there are variations that are determined by ________________ ________________.
Heredity, environment, both factors
Variations determined by heredity are called ________________ ________________ (or ________________ ________________). These variations ________________ __________ __________________ as they are ____________ _______________ __________ ________________ ______________________.
inherited variations, genetic variations, cannot be changed, not affected by the environment
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natural hair colour, natural eye colour, most discontinuous variations
Variations determined by the environment are called __________________ ________________.
environmental variations
Examples of environmental variations:
- ________________ rabbit
- ________________ colour around the __________, _____________, __________ and ________________ changes with the environment
- ________________
- its ________________ varies depending on the ________________ of the ________________ which it grows
Himalayan, dark, ears, nose, legs, tail
Colour, conditions, soil
Examples of variations caused by both environment and heredity: ________________ ________________
The ________________ ________________ we’ve learnt are usually determined by both heredity and the environment.
skin colour, continuous variations
In rare cases where __________ embryos develop at the ______________ time, the ___________ babies born from a ________________ pregnancy are called ________________.
two, same, two, single, twins
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 ________________ ________________ ________________ ________________.
single zygote, zygote, two cells, same genetic materials, same gender, look like each other
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.
two ova, ovary, same time, fertilised
different genetic materials, ova, sperm
two separate pregnancies, same gender, different gender, look different
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 ____________________.
identical twins can still have variations in their features
difference, living habits, environments
height, body mass, exercises, eating habits, skin colours, levels, exposure, sunlight
A DNA consists _____________ _______________. On the strands there are _____________ different kinds of ______________: _____, _____, _____, and ____ for short.
two strands, four, bases, A, T, C, G
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 _____________ __________ ______________.
bases, strands, double helix, A,T, C, G, complementary base pairing, sequence, complementary bases, also be known
The ______________ of _____________ on DNA acts as ______________ ______________. It encodes ‘______________’ that determine our ______________.
sequence, bases, genetic code, messages, traits
Every ______________ bases of a DNA strand encode __________ ‘message’, so it is called a ______________ ______________. These ‘messages’ are actually __________________ for the ____________ to _______________________________________________________________.
three, one, triplet code, instructions, cells, make different types of proteins in the body
