Download File - cOACH RICH`S BIOLOGY CLASS

Bell work 10-27
Copyright© 2015 EducAide Software Inc. All rights reserved.
Copyright© 2015 EducAide Software Inc. All rights reserved.
Reminders
• Test corrections during AST,
before or after school
• End of three weeks is
TOMMORROW
• Cell cycle and DNA test 11-6
counted
Quiz about DNA
Today in class
describe the stages of the cell cycle,
including deoxyribonucleic acid
(DNA) replication
Talk about how DNA is replicated
Review about DNA
What is the structure
below called?
What are the three pieces
that make up a nucleotide?
Phosphate
Nitrogen Base
Sugar
What kinds of bonds exists
between the Bases of DNA?
Watson and Crick found
that DNA was in the
shape of an?
Adenine always binds with______
Cytosine always binds with_____
Thymine always binds with_____
Guanine always binds with_____
Gerenal Chrmosomes
• DNA: Directs cell activity
• Gene: a segment of DNA that
transmits information.
• Chromosome: a single DNA
molecule and its associated
proteins.
• Chromatid: copy of a chromosome.
Chromosomes
Prokaryotes
1. DNA is found in the
cytoplasm (nucleiod region)
2. Single circular DNA
molecules
3. DNA replication begins at a
single point in the
chromosome & proceeds in
both directions until the
chromosome is replicated
Eukaryotes
1. Found in the nucleus
2. Chromosome number
varies between species
3. DNA replication occurs
at hundreds of places
called replication forks
Chromosomes
How much DNA in a human nucleus?
• more than 1 meter
What is chromatin?
• DNA tightly coiled around proteins called histones
Chromosomes
How are chromosomes constructed?
1. DNA & histones form beadlike structures called
nucleosomes
2. Nucleosomes pack with one another to form thick fibers
3. Fibers are shortened by a system of loops & coils
Replication
Replication – General Info
• The exact copying of DNA
• Replication occurs in both directions
• DNA must be copied before cells divide 
each daughter cell has a complete set of DNA
• Original strands serve as templates for new
strands
Replication – General Info
How it happens:
1. Helicase (enzyme) unwinds the DNA by breaking
hydrogen bonds
Replication – General Info
2. DNA polymerase (enzyme) joins individual nucleotides to
each separated strand, producing DNA molecule
3. DNA polymerase also proofreads each new DNA strand to
make perfect copies
Replication – General Info
Results: 2 DNA molecules  each contains one original
strand & one new strand
Sometime a MUTATION
can occur
Changes in DNA that affect genetic
information
What Causes
Mutations?
• There are two ways in which DNA can
become mutated:
– Mutations can be inherited.
• Parent to child
– Mutations can be acquired.
• Environmental damage
• Mistakes when DNA is copied
How are they inherited
Only mutations to the gametes (egg
and sperm cells) can be passed on
to offspring.
Mutations in body cells only affect
the organism in which they occur.
They cannot be passed on to
offspring.
Significance of
Mutations
• Most are neutral
• Eye color
• Birth marks
• Some are harmful
• Sickle Cell Anemia
• Down Syndrome
• Some are beneficial
• Sickle Cell Anemia to Malaria
• Immunity to HIV
DNA Cut and Paste
Directions:
1. Cut out the following shapes.
2. Fold the color of paper that corresponds to the shape that you
are cutting so that you do not have to cut so many (4 at time is
good).
3. The following are the color combinations for the shapes
–
–
–
–
–
–
Yellow – 4 A shapes – write A on both side of the paper
Green – 4 G shapes – write G on both sides
Blue – 4 T shapes – write T on both sides
Orange – 4 C shapes – write C on both sides
White – 16 S shapes – write S on both sides
Black – 16 P shapes – write P on both sides
4. You are now going assemble 16 individual nucleotides,
matching the dots (*) to dots and pluses (+) to pluses. Use glue
to hold the nucleotides together.
Table of Contents
Pre-AP only Root words page 74
Cell Cycle notes page 75-76
DNA notes page 77
DNA Double Helix Activity 78-79
DNA Cut and Paste paper 80
Bell work page 81
DNA Replication 82-83