Science 9
Life Science Unit
Reproduction and Human
Development
Introduction to Cells and Genetics
 The wacky history of cell theory
http://ed.ted.com/lessons/the-wacky-history-of-cell-theory
Cell theory states:
All organisms are composed of one or more
cells.
The cell is the basic unit of life.
All cells come from pre-existing cells
Cell theory was first proposed by German
scientists Theodor Schwann and Matthias
Schleiden.
Introduction to Cells and Genetics
Cells contain a complete copy of the
genetic information that gives an individual
organism the traits that make it what it is
and not something else.
Cells have life cycles. They are
created, live, reproduce, and die.
It is during the process of
reproduction, or cell division, that
genetic information is passed along.
Introduction to Cells and Genetics
 There are two types of cells, prokaryotes and eukaryotes.
Prokaryotes are simple cells which usually make up
bacteria or single cell organisms.
Eukaryotes are more complex cells which usually
make up plants and animals.
Introduction to Cells and Genetics
Nucleus
 Genetic material is located in nucleus. It’s basically the
brains of the operation, it tells cells how to reproduce
and how something is made.
Chromosomes
 Chromatin is located in the nucleus. Chromatin organizes
itself into chromosomes during cell division. Chromosomes
contain DNA.
 Each organism depending on its complexity varies in the
amount of chromosomes it has. There are 46
chromosomes (23 pairs) in the human body. Whereas a
frog has 13 pairs.
Introduction to Cells and Genetics
DNA
 The genetic information is stored in Deoxyribonucleic
acid, DNA
 DNA contains the information needed to build an
individual.
Genes
 DNA is made up of genes. There are many individual genes
withing the DNA and they contain the information that is
needed to transfer specific traits from one oganism to
another during reproduction.
Introduction to Cells and Genetics
Homework
1. What are some of the specific traits you inherited from your
parents or features you have in common with your
siblings? (make a list)
2. Research two genetic conditions that scientists are
currently trying to learn more about its relation to genetics.
How can we better understand its link to genetics in order
to prevent or cure?
3. Who was Gregor Mendel? What did he contribute to the
study of genetics? State the 7 traits he observed.
Introduction to Cells and Genetics
Read more:
http://www.scienceclarified.com/scitech/Genetics/Genes-andDNA.html
http://www.dnatutorial.com/DNAChromosomes.shtml
http://anthro.palomar.edu/mendel/mendel_1.htm
Heredity and Genetic Traits
Supportive Links to videos and worksheets
 http://learn.genetics.utah.edu/content/inheritance/intro/
 http://learn.genetics.utah.edu/content/inheritance/traits/
 http://learn.genetics.utah.edu/content/inheritance/patterns/
 http://learn.genetics.utah.edu/content/inheritance/activities/pd
fs/Inherited%20Human%20Traits%20Quick%20Reference_P
ublic.pdf
Heredity and Genetic Traits
Define:
 Allelle
 genotype
 Phenotype
 Recessive trait
 Dominant trait
 Homozygous
 heterozygous
Additional Reading:
 http://www.merckmanuals.com/home/fundamentals/genetics/
genes_and_chromosomes.html?qt=&sc=&alt=
Cellular Reproductive Processes
In general, in order for cells to reproduce they make
a copy of their genetic material and then they divide.
A parent cell gives rise to daughter cells.
We are going to study three basic ways in which
cells reproduce.
Binary Fission
Mitosis
Meiosis
Cellular Reproductive Processes
Binary Fission
This process occurs in Prokaryote Cells (cells
with no nucleus), like bacteria. The DNA is
duplicated, and then the cell splits apart. The
two cells will be exact replicas of one another,
containing the same number of chromosomes.
http://www.youtube.com/watch?v=3cD3U2pgb5w
Cellular Reproductive Processes
Mitosis
In this process the cell will copy all of its’ DNA (remember
two matching strands) to make two complete sets so that
one set can be sent to each of the daughter cells. This is
cell division in which the chromosome number remains the
same, diploid to diploid. Mitosis is used for most of the cell
division that occurs within your body and for most
development and growth of living things.
Cellular Reproductive Processes
Cell Cycle
Complete the cell cycle and mitosis note
pages from the following web link
http://www.biologyjunction.com/biology_color
ing_worksheets.htm
Cellular Reproductive Processes
Meiosis
In this process the cell will copy all of its’ DNA and make
two complete sets, and then it will split into two cells so
that there is one complete set of DNA in each of the two
daughter cells. These two daughter cells will then split
again, making four cells each with a single strand of DNA.
This is cell division in which the chromosome number is
halved, or from diploid to haploid. Meiosis is used to
create the cells used for sexual reproduction.