Download Sec 16.3 Sexual Reproduction

Chapter 16 – Cell Reproduction
Science 10
Sec 16.3 Sexual Reproduction
- requires two parents
- produces offspring that are not identical to each other
- requires specialized cells which ONLY function in reproduction ( egg
and sperm)
Karyotype
- a picture set of the chromosomes
- humans have 23 pairs of
chromosomes
Each pair is homologous – made up
of the same kinds of genes
For example;
chromosome #14 could code for
hair color, #11 – eye color
Diploid – cells that contain pairs of chromosomes
All normal body cells are diploid, therefore they contain 23 pairs of
chromosomes = 46 chromosomes in total.
Sex chromosomes (humans have 1 set)
Female - sex chromosomes are homologous (XX)
Male - sex chromosomes are non-homologous (XY)
Draw figure 16.16 pg 368
Chapter 16 – Cell Reproduction
Science 10
What happens when there are two parents?
- 2 cells join, 1 from each parent, to form the first cell.
- If each of these cells contained a full set of chromosomes, then the new
cell would have double the amount that it should.
 This is a problem!
The solution is simple,
The 2 reproductive cells, that join should only have HALF of the
number of chromosomes, so when they join the new cell has the correct
number of chromosomes
Haploid – the reproductive cells (sex cells) are haploid
- only have 1 SET of chromosomes NOT PAIRS
Haploid reproductive cells are called gametes
Gametes contain 23 chromosomes NOT 23 pairs of chromosome.
How does a diploid sex cell become a haploid sex cell?
MEIOSIS
The basics – 1 diploid sex cell will eventually turn into 4 haploid gametes
The steps of meiosis:
INTERPHASE – MEIOSIS I – INTERPAHSE – MEIOSIS II - CYTOKINESIS
PMAT I
PMAT II
Chapter 16 – Cell Reproduction
Science 10
Meiosis
Occurs in 2 parts, meiosis I and meiosis II
each parts has 4 sections – PMAT – same as Mitosis
Interphase is first
Meiosis I
Prophase I – Metaphase I – Anaphase I – Telophase I
Interphase – this time the chromosomes DO NOT get duplicated
before meiosis II starts
Meiosis II
Prophase II – Metaphase II – Anaphase II – Telophase II
Cytokinesis
The result is 4 haploid daughter cells.
Gametes are made by meiosis, 2 gametes must come together to form a new
organism because each gamete only has half of the number of
chromosomes.
Science 10
Chapter 16 – Cell Reproduction
In Humans
Female gamete – is called an EGG or OVUM
Male gamete - is called a SPERM or SPERMATOZOON
Fertilization occurs when a sperm penetrates the egg and the 2 sets of
chromosomes fuse together to create the proper number of chromosomes,
in humans = 46.
The new cell is called a zygote, with two sets of chromosomes (diploid). It
is the first cell of a new organism.
The zygote will divide by mitosis, when it starts to divide it is called an
embryo.
The embryo grows and grows ( the cells divide a lot of times) until it
develops features and body structures. It is now called a fetus. 9 months
later it is crying for help and asking for money!
Chapter 16 – Cell Reproduction
Science 10
Sec 16.3 Sexual Reproduction
-
requires two parents
produces offspring that are not identical to each other
requires specialized cells which ONLY function in reproduction ( egg and sperm)
Karyotype
- a picture set of the chromosomes
- humans have 23 pairs of chromosomes
Each pair is homologous – made up of
the same kinds of genes
For example;
chromosome #14 could code for hair color,
#11 – eye color
Diploid – cells that contain pairs of chromosomes
All normal body cells are diploid, therefore they contain 23 pairs of chromosomes =
46 chromosomes in total.
Sex chromosomes (humans have 1 set)
Female - sex chromosomes are homologous (XX)
Male - sex chromosomes are non-homologous (XY)
Draw figure 16.16 pg 368
Chapter 16 – Cell Reproduction
Science 10
What happens when there are two parents?
-
2 cells join, 1 from each parent, to form the first cell.
If each of these cells contained a full set of chromosomes, then the new cell would have
double the amount that it should.

This is a problem!
The solution is simple,
The 2 reproductive cells, that join should only have HALF of the number of
chromosomes, so when they join the new cell has the correct number of chromosomes
Haploid – the reproductive cells (sex cells) are haploid
- only have 1 SET of chromosomes NOT PAIRS
Haploid reproductive cells are called gametes
Gametes contain 23 chromosomes NOT 23 pairs of chromosome.
How does a diploid sex cell become a haploid sex cell?
MEIOSIS
The basics – 1 diploid sex cell will eventually turn into 4 haploid gametes
The steps of meiosis:
INTERPHASE – MEIOSIS I – INTERPAHSE – MEIOSIS II - CYTOKINESIS
PMAT I
PMAT II
Meiosis
Occurs in 2 parts, meiosis I and meiosis II
each parts has 4 sections – PMAT – same as Mitosis
Interphase is first
Meiosis I
Prophase I – Metaphase I – Anaphase I – Telophase I
Interphase – this time the chromosomes DO NOT get duplicated
before meiosis II starts
Meiosis II
Prophase II – Metaphase II – Anaphase II – Telophase II
Cytokinesis
Science 10
Chapter 16 – Cell Reproduction
The result is 4 haploid daughter cells.
Gametes are made by meiosis, 2 gametes must come together to form a new organism
because each gamete only has half of the number of chromosomes.
In Humans
Female gamete – is called an EGG or OVUM
Male gamete - is called a SPERM or SPERMATOZOON
Fertilization occurs when a sperm penetrates the egg and the 2 sets of chromosomes fuse
together to create the proper number of chromosomes, in humans = 46.
The new cell is called a zygote, with two sets of chromosomes (diploid). It is the first cell of
a new organism.
The zygote will divide by mitosis, when it starts to divide it is called an embryo.
The embryo grows and grows ( the cells divide a lot of times) until it develops features and
body structures. It is now called a fetus. 9 months later it is crying for help and asking for
money!
Chapter 16 – Cell Reproduction
Science 10
Sec 16.3 Sexual Reproduction
-
____________________
produces offspring that are _______________________________
requires specialized cells which ________________________________ ( egg
and sperm)
______________
- a ___________ of the chromosomes
- humans have __________ of
chromosomes
- Each pair is ____________ – made
up of the same kinds of genes
For example;
chromosome #14 could code for hair color,
#11 – eye color
Diploid – ___________________________________
All normal body cells are diploid, therefore they contain 23 pairs of chromosomes =
_______________________ in total.
Sex chromosomes (humans have 1 set)
Female - sex chromosomes are homologous (_____)
Male - sex chromosomes are non-homologous (_____)
Draw figure 16.16 pg 368
Chapter 16 – Cell Reproduction
Science 10
What happens when there are two parents?
-
2 cells join, 1 from each parent, to form the first cell.
If each of these cells contained a full set of chromosomes, then the new cell would have
_______________________ that it should.

This is a problem!
The solution is simple,
The 2 reproductive cells, that join should ___________________________
______________________________ of chromosomes, so when they join the new cell
has the correct number of chromosomes
_________– the reproductive cells (sex cells) are haploid
- only have ________ of chromosomes ____________
Haploid reproductive cells are called ____________
Gametes contain 23 ________ chromosomes NOT 23 _______ of chromosome.
How does a diploid sex cell become a haploid sex cell?
MEIOSIS
The basics – ____________________________________________________
The steps of meiosis:
___________– __________– __________ – ____________- ____________
PMAT I
PMAT II
Meiosis
Occurs in 2 parts, meiosis I and meiosis II
each parts has 4 sections – PMAT – same as Mitosis
____________ is first
____________
Prophase I – Metaphase I – Anaphase I – Telophase I
____________ – this time the chromosomes DO NOT get duplicated
before meiosis II starts
____________
Prophase II – Metaphase II – Anaphase II – Telophase II
_____________
Science 10
Chapter 16 – Cell Reproduction
The result is 4 haploid daughter cells.
____________ are made by ____________, 2 gametes must come together to form a
_______________because each gamete only has ______ of the number of
chromosomes.
In Humans
____________ gamete – is called an ____________ or ____________
____________ gamete - is called a ____________ or ____________
____________ occurs when a ____________penetrates the ____________and the 2
sets of chromosomes ________________to create the proper number of chromosomes,
in humans = _____.
The new cell is called a ____________, with ____ sets of chromosomes (diploid). It is
the first cell of a new organism.
The zygote will divide by mitosis, when it starts to divide it is called an ____________.
The embryo grows and grows ( the cells divide a lot of times) until it develops features and
body structures. It is now called a ____________. 9 months later it is crying for help and
asking for money!