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Genetics. ( Part One). By Group 3. Name: Poon Wing Ching (Prudence) Tse Man Ki (Annie) Wong Chi Yin (Stanley). Contents. Revision & Introduction. What is Genetics?. What determines our characteristics?. Summary. Self-learning Exercises. Revision on Reproduction. True or False.

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Genetics

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Genetics

(Part One)

By Group 3

Name: Poon Wing Ching (Prudence)

Tse Man Ki (Annie)

Wong Chi Yin (Stanley)


Contents

Revision & Introduction

What is Genetics?

What determines our characteristics?

Summary

Self-learning Exercises


Revision on Reproduction

True or False

Q1. Pollen grains are the male gametes.

True

False


Revision on Reproduction

True or False

Q2. In flowering plants, ovaries will develop

into seed

True

False


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


Revision on Reproduction

True or False

Q4. The umbilical cord is a structure for

attachment of the embryo to the

uterine wall.

True

False


Right, you are correct!!!

  • Pollen grains are the carries of male gametes


Right, you are correct!!!

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


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.


Right, you are correct!!!

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


Sorry, you’re wrong!!!

Pollen grains are the carries of male gametes


Sorry, you’re wrong!!!

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


Sorry, you’re 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.


Sorry, you’re wrong!!!

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


Introduction

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

  • Do you look like your parents?

:-) Why do we resemble our parents?


What is genetics(遺傳學)?

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


What determines our characteristics?

  • Gene, DNA & Chromosomes

Genes(基因):

  • basic unit of heredity

  • present on chromosome

  • Genes are short lengths of DNA on chromosome


Gene, DNA & Chromosomes (Cont’d)

  • determine the sequences of amino acids

Genes:(Cont’d)

  • controls protein synthesis

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


Gene, DNA & Chromosomes (Cont’d)

  • DNA

    (Deoxyribose nucleic acid 去氧核糖核酸)

  • genetic material determining body characters by controlling types of protein produced


  • Gene, DNA & Chromosomes (Cont’d)

Chromosome(染色體):

  • genetic materials found inside the nucleus of the cell

  • one from female parent

  • made of protein & DNA

  • each kind of organism has a specific no. of chromosome e.g. man:46

  • exist in pairs in body cell

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

  • one from male parent


The role of gametes

  • As vehiclesof inheritance

Fusion of a male & female gametes

zygote

organism


  • 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


Meiosis(減數分裂)

Meiotic cell division including meiosis

and division of cytoplasm

Quicktime Movies of

Stages in meiotic cell division:

First meiotic division

Second meiotic division


  • Significance of meiosis

  • Halving of chromosome no.:

  • producing gametes which have different genetic make - up

  • 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:


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


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


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.


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


Sorry, you’re wrong!!!

Gametogenesis: gamete production

Try again!!!


Sorry, you’re wrong!!!

Implantation: event during fertilized egg becomes embedded in uterine wall

Try again!!!


Sorry, you’re wrong!!!

Pregnancy: having in the uterus offspring in a stage of development before birth

Try again!!!


Congratulations!!!

Fertilization: union of male (sperm) and female (egg) gametes

You’ve

got the

correct

answer!

Next


Self-Learning Exercise

Q2: How gametes are formed?

A. Meiotic cell division

B. Meiosis

C. Mitosis

D. Mitotic cell division


Congratulations!!!

Gametes are formed by a process called meiotic cell division, including meiosis and division of cytoplasm

Next


Sorry, you’re wrong!!!

Meiosis is a kind of nuclear division.

Try again!!!


Sorry, you’re wrong!!!

Mitosis is a kind of nuclear division for increasing no. of cell

Try again!!!


Sorry, you’re wrong!!!

Mitotic cell division including mitosis and cytoplasm division

Try again!!!


Self-Learning Exercise

Q3: Inherited characteristics are determined by?

A. DNA

B. Chromosomes

C. Genes

D. Proteins


Sorry, you’re wrong!!!

DNA provides the genetic information to control protein synthesis

Try again!!!


Sorry, you’re wrong!!!

Chromosome carries genes

Try again!!!


Congratulations!!!

Inherited characters are determined by genes

Go to End


Sorry, you’re wrong!!!

Proteins control body characteristics and metabolic activities

Try again!!!


Further Reading

Science Learning Network

Biological Science Page


The End


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