Download UNIT 2: Genetic Processes

UNIT 2: Genetic Processes
What is genetics?
• Genetics is the study of heredity and the
variation of inherited characteristics
– how genetic information is passed from one
generation to the next
• But to understand these processes, we must
first review the mechanism by which cells
divide.
Agenda
Chapter 4: Cell Division and Genetic Material
• Stages of the Cell Cycle
• Mitosis
• The Structure of Genetic Material
Cell Theory
1. All living things are composed of
one or more cells
2. Cells are the smallest units of living
organisms
3. New cells come only from preexisting cells by cell division
3. New cells come only from preexisting cells by cell division
• “Pre-existing cell” = parent cell
• New cells = daughter cells
When a cell divides, each new
cell receives genetic information
from the parent cell
 What is a somatic cell?
The Cell Cycle
• Interphase
– (G1)Cell growth
– (S) Genetic material
copied
– (G2) Preparation
• Mitosis
– Division of nucleus
& genetic material
• Cytokinesis
– Division of the
cytoplasm
– Creation of new cell
Mitosis
The key activity of mitosis is the accurate separation
of the cell’s replicated DNA
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Prophase
Metaphase
Anaphase
Telophase  Cytokinesis
• Animal cells vs Plant Cells vs Prokaryotic Cells
Key Words
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Chromatin (Interphase)
Chromosome (in Prophase vs Anaphase)
(Sister) Chromatids
Centromere
Spindle fibres
Centrosomes
What is Cancer?
• Occurs when something interferes with signals
that regulate cell growth
• The result of uncontrolled, rapid, cell division
• Cancer cells divide so quickly that it results in
a mass of cells that accumulate and form a
tumor
The Structure of Genetic Material
• DNA
• Double Helix
• Nucleotide = Sugar
+ Phosphate + Base
• Histones
Chromosome Pairing
The number of individual chromosomes in each
cell varies from one species to the next
• Human somatic cells have 46 chromosomes
– How many chromosomes are in gametes?
• In each pair, one chromosome came from the
father and the other came from the mother
• Humans have one pair of sex chromosomes
and 22 pairs of autosomes.
Homologous Chromosomes
• Not to be confused with sister chromatids
• They are pairs of chromosomes that appear similar in
length, centromere location, and banding pattern
• The above is what is known as a Karyotype
Homologous Chromosomes
… are NOT identical
• Have the same genes but different alleles
Gene: a part of a chromosome that codes for a
certain trait (with a specific DNA sequence)
Allele: a different form of the same gene
Different “forms” account for differences in
specific traits such as hair colour
Homework
• Handout to be completed and submitted by
Wednesday
• Pg. 168 #1,3,5,10-14
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