Transcript genetics_self learning

(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)
Genes:(Cont’d)
determine the sequences
of amino acids
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
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
one from female parent
The role of gametes
As vehicles of inheritance


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
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
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
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