Genetics

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• Genetics

(Part One)
By Group 3
Name Poon Wing Ching (Prudence) Tse Man Ki
(Annie) Wong Chi Yin (Stanley)
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Contents

• Revision Introduction

• What is Genetics?

• What determines our characteristics?

• Summary

• Self-learning Exercises

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Revision on Reproduction
True or False
Q1. Pollen grains are the male gametes.
True
False
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Revision on Reproduction
True or False
Q2. In flowering plants, ovaries will develop
into seed
True
False
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Revision on Reproduction
True or False
Q3. Gardeners sometimes use seeds to
produce new plants for flowers because
this method has an advantage of
preventing overcrowding as compared with
vegetative propagation.
True
False
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Revision on Reproduction
True or False
Q4. The umbilical cord is a structure for
attachment of the embryo to the uterine
wall.
True
False
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Right, you are correct!!!

• Pollen grains are the carries of male gametes

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Right, you are correct!!!

• In flowering plants, ovaries will develop into
  fruits, whereas the ovules will develop into
  seeds.

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Right, you are correct!!!

• Prevention of overcrowding is an advantage for
  plant dispersal only. Gardeners using seeds to
  produce new plants of flower, because this method
  can produce variations which may give rise to
  flowers of better quality. Such an advantage is
  not found in vegetation propagation.

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Right, you are correct!!!

• The umbilical cord connects the embryo to the
  placenta instead of the uterus.

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Sorry, youre wrong!!!
Pollen grains are the carries of male gametes
12
Sorry, youre wrong!!!
In flowering plants, ovaries will develop into
fruits, whereas the ovules will develop into
seeds.
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Sorry, youre wrong!!!
Prevention of overcrowding is an advantage for
plant dispersal only. Gardeners using seeds to
produce new plants of flower, because this method
can produce variations which may give rise to
flowers of better quality. Such an advantage is
not found in vegetation propagation.
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Sorry, youre wrong!!!
The umbilical cord connects the embryo to the
placenta instead of the uterus.
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Introduction

• Can you guess who is the son of Mr. Simpson
  ?

• Do you look like your parents?

-) Why do we resemble our parents?
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What is genetics(???)?

• The study of how characteristics are passed from
  generation to generation.

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What determines our characteristics?

• Gene, DNA Chromosomes

Genes(??)

• basic unit of heredity
• present on chromosome

• Genes are short lengths of DNA on chromosome

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Gene, DNA Chromosomes (Contd)

• Genes(Contd)

• determine the sequences of amino acids

• controls protein synthesis

• Indirectly controls the appearance of characters
  and metabolic activities of an organism

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Gene, DNA Chromosomes (Contd)

• DNA
• (Deoxyribose nucleic acid ??????)
• genetic material determining body characters by
  controlling types of protein produced

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• Gene, DNA Chromosomes (Contd)

Chromosome(???)

• genetic materials found inside the nucleus of the
  cell

• made of protein DNA

• each kind of organism has a specific no. of
  chromosome e.g. man46

• exist in pairs in body cell

• the members of each pair of chromosome is called
  Homologous chromosomes

• one from male parent

• one from female parent

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The role of gametes

• As vehicles of inheritance

• Fusion of a male female gametes

?

• zygote

?

• organism

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• How gametes are formed?

• by the process meiotic cell division

• The major task of meiosis is to produce haploid
  gametes

• in the process of meiosis, crossing over can occur

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Meiosis(????)

• Meiotic cell division including meiosis
• and division of cytoplasm

• Quicktime Movies of
• Stages in meiotic cell division

• First meiotic division

• Second meiotic division

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• Significance of meiosis

• Halving of chromosome no.

• The no. of chromosome can be restored at
  fertilization

• think of what would happen if human gametes were
  produced by mitosis?

• Independent assortment of chromosomes

• producing gametes which have different genetic
  make - up

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Mitosis Vs Meiosis
Questions on comparing meiotic mitotic cell
divisions
1. Occurrence
2. Pairing of homologous chromosomes
3. Separation of homologous chromosomes
4. Number of division
5. Number of daughter cells produced from each
parent cells
6. Type of daughter cells
7. Chromosome number of daughter cells
8. Function
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Summary
1. Gametes are formed by meiosis. (reduction
division)
2. Meiotic cell division includes pairing and
separation of homologous chromosomes, separation
of chromatids and formation of four daughter cells
3. Meiotic cell division is significant in
A.) forming haploid gametes, so diploid number of
chromosomes can be restored at fertilization
B.) producing gametes which have different
genetic make-up
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Wrong Concepts
1. Meiosis is a kind of cell division.
Meiosis involves division of nucleus alone. This
is only a kind of nuclear division. Cell
division includes cytoplasmic and nuclear
division.
2. Every characteristic is controlled by a pair
of genes.
Many characteristics are controlled not by one of
genes, but by many genes, e.g. height of man.
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Self-Learning Exercise
Q1 What is the name for the process of fusion of
male and female gametes?
A. Gametogenesis
B. Implantation
C. Pregnancy
D. Fertilization
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Sorry, youre wrong!!!
Gametogenesis gamete production
Try again!!!
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Sorry, youre wrong!!!
Implantation event during fertilized egg becomes
embedded in uterine wall
Try again!!!
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Sorry, youre wrong!!!
Pregnancy having in the uterus offspring in a
stage of development before birth
Try again!!!
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Congratulations!!!
Fertilization union of male (sperm) and female
(egg) gametes
Youve got the correct answer!
Next
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Self-Learning Exercise
Q2 How gametes are formed?
A. Meiotic cell division
B. Meiosis
C. Mitosis
D. Mitotic cell division
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Congratulations!!!
Gametes are formed by a process called meiotic
cell division, including meiosis and division of
cytoplasm
Next
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Sorry, youre wrong!!!
Meiosis is a kind of nuclear division.
Try again!!!
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Sorry, youre wrong!!!
Mitosis is a kind of nuclear division for
increasing no. of cell
Try again!!!
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Sorry, youre wrong!!!
Mitotic cell division including mitosis and
cytoplasm division
Try again!!!
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Self-Learning Exercise
Q3 Inherited characteristics are determined by?
A. DNA
B. Chromosomes
C. Genes
D. Proteins
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Sorry, youre wrong!!!
DNA provides the genetic information to control
protein synthesis
Try again!!!
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Sorry, youre wrong!!!
Chromosome carries genes
Try again!!!
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Congratulations!!!
Inherited characters are determined by genes
Go to End
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Sorry, youre wrong!!!
Proteins control body characteristics and
metabolic activities
Try again!!!
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Further Reading

• Science Learning Network

• Biological Science Page

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• The End