Concepts Of Biology
Concept Topic 11 [Week #12] Cell Reproduction
12.1 DNA Structure Revealed
12.3 An Introduction to the Cell Cycle and Mitosis
12.2 Events of DNA Replication 12.4 Meiosis
12.7.1 DNA Fingerprinting
12.5 Human genome Project
Lecture Review Topic: Cell Reproduction
What is a gene ?
Where is it located ?
How is it passed on ?
Genetic Material: Nucleic Acids = DNA - Deoxyribonucleic acid & RNA Ribonucleic acid
I.
DNA - Deoxyribonucleic acid
Thinkwell Topics
12.1 DNA Structure Revealed
12.1.1 Watson and Crick: The Double Helix
12.2 Events of DNA Replication
OMIT 12.2.1, 12.2.2, 12.2.3 and 12.2.4
12.2.5DNA Replication: A Summary
A.
B.
Structure of DNA
1.
Synthesized and Located:
1.
Nucleus, chromosomes, Linear DNA = Main Genetic code for organism
2.
Mitochondrial matrix, Circular DNA= limited to genes in Mitochondria
3.
Chloroplast matrix, Circular DNA= limited to genes in Chloroplast
2.
Characteristics of the Genetic Material
1.
Replication
2.
Storage of Information
3.
Expression of Information
4.
Variation by mutation
3.
DNA Composition:
1.
Double Helix, Antiparallel strands
2.
Composed of Nucleotide subunits
3.
Nucleotides:
a.
Adenine
b.
Cytosine
c.
Thymine
d.
Guanine
Criteria of the Genetic Material
1.
Storage of Genetic Information
C.
2.
Expression of Information (Template for RNA synthesis,
3.
Replication of Genetic Information, passing it to new cells
4.
Variation by Mutation (changes in Genetic Information[DNA])
Duplication of DNA (Semiconservative Replication)
1.
Double Strand Formation= Adenine bonds with Thymine, Cytosine bonds with Guanine
2.
Strands Separate
1.
Adenine nucleotide in cytoplasm bonds with Thymine in template strand
2.
Cytosine nucleotide in cytoplasm bonds with Guanine in template strand
3.
Thymine nucleotide in cytoplasm bonds with Adenine in template strand
4.
Guanine nucleotide in cytoplasm bonds
with Cytosine in template strand
3.
2 new strands resemble original strands in sequence
of nucleotides
4.
SUMMARY Steps in replication (S phase of cell
cycle)
Break, Unwind, Replicate, Mend
1.
Strands Unravel - helicase (enzyme that
unwinds & hold apart) Blue
2.
Strands Separate - Replication Fork Yellow
3.
RNA polymerase produces a RNA primer,
which attract DNA polymerase
4.
DNA polymerase brings in complementary nucleotides & proof reads strand
5.
Ligases (enzymes) bind nucleotides together in new strand
6.
RNA Primer removed by DNA Polymerse I and DNA ligase
[Have an understanding of the process but NOT required to know names of enzymes, see
diagram at right & notes]
Thinkwell Topics
12.7 More Techniques in Biotechnology
12.7.1 DNA Fingerprinting
D.
DNA Fingerprinting
A. Uniquely identifies individuals on the basis of DNA fragment lengths.
B. Fragments are generated by restriction enzymes that cut DNA at specific sites.
C. Each individual�s DNA fragments are different enough that these enzymes will generate
different lengths of fragments in two different individuals.
Procedure:
1.
DNA is usually obtained from two sources: [Blood or Hair at a crime scene]
2.
Polymerase chain reaction is used to make many copies.
3.
Restriction enzymes are used to cut the DNA into fragments.
4.
The fragments are separated by electrophoresis.
5.
The patterns of the two DNA samples are compared.
D. DNA fingerprinting can identify if two samples of DNA came from the same or
different person.
E. Used in the prosecution of crime suspects
F. Used in paternity cases or to solve other identity problems
E.
Lecture Review Topics Cell Cycle and Division
Thinkwell Topics
12.3 An Introduction to the Cell Cycle and Mitosis
12.3.1 The Eukaryotic Cell Cycle
12.3.2 Mitosis: An Overview
12.3.3 Mitosis: The Phases
12.3.4 Cytokinesis
0.
Cell Cycle and Chromosome Transmission
A. Human Chromosomes, Karyotype (See below)
B. Cell Cycle
1. G1, S, G2, M phases
1.
G1, Gap 1 = DNA for one set of chromosomes, growth of the
cell
2.
S-phase = DNA synthesis prior to both Mitosis & Meiosis
3.
DNA in cell doubles (complete new set formed)
4.
G2, Gap 2 = DNA for two sets of chromosomes, Mitotic Prep
5.
M phase Mitosis. simple Cell division or Meiosis, reduction
division
1.
Mitosis
.
C.
Simple Cell Division (one cell produces two, same kind & number of chromosomes)
A. Human Cells (46 per cell, two of each chromosome )
B. Chromosomes, After S phase, 2 chromatids joined at the centromere
Phases of Mitotic Process
0. Prophase
a. Chromatin => Chromosomes
b. Loss of Nuclear Membrane
c. Loss of Nucleolus
d. Development of Mitotic Apparatus [Spindle of microtubeles]
1. Metaphase
. Chromosomes line up in a single layer along the equator of cell.
a. Chromosomes attach to spindle fibers
b. Centromere divides, chromatids become "new chromosomes"
2. Anaphase
. New chromosomes pulled to oposite ends of the cell
a. Spindle elongates
b. Cell elongates
3. Telophase
. Chromosomes => Chromatin
a. New Nuclear Membranes forms
b. New Nucleolus forms
c. Mitotic Apparatus [Spindle of microtubules] disappears
d. Cytoplasm divides into TWO NEW CELLS (Cytokinesis)
4. Cytokinesis
. Division of the Cytoplasm
a. Begins during late Anaphase
b. Completed during Telophase
c. Differs in Plants & Animals
D.
Online Onion Root Tips
See Project Link in Blackboard under Discussions
1. Determining time spent in different phases of the cell cycle
2. http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle
.html
Meiosis = Reduction Division (next week: as found in Ovaries, Testis)
0.
2.
Thinkwell Topics
12.4 Meiosis
12.4.1 Sexual Reproduction and the Role of Meiosis
12.4.2 Homologous Chromosomes: Thanks, Mom and
Dad!
.
12.4.3 Meiosis: Prophase I
12.4.4 Disjunction and
Meiosis II
12.4.5 Mitosis vs. Meiosis
Production of 4 cells with one half the number of chromosomes
A. Chromosomes, After S phase = 2 chromatids joined at the centromere, Same as
in Mitosis
B. Two Step division process
0. Meiosis I
. Separation of Chromosome Pairs
a. Long Prophase, Joining of chromosome pairs
b. Metaphase, double layer of chromosomes
c. Anaphase, Separation of Chromosome Pairs
1. Meiosis II
. Separation of Chromatids
a. Mitotic process with half the number of Chromosomes
3.
Human Cells and Human Chromosomes
Body cells = 46 chromosomes per cell, 2 of each set
Sperm or Egg Cell = 23 chromosomes per cell, one of each set
II.
HUMAN GENOME PROJECT
Thinkwell Topics
12.5 Human Genome Project
12.5.1 The Human Gene Pool
1.
The Human Genome Project
.
B.
A massive collaborative effort to determine the sequence of DNA in all human
chromosomes.
0. Started with physical maps of chromosomes
1. Determines the location of specific markers on the chromosomes
2. DNA sequencing determines the exact nucleotide sequence
between each chromosome marker.
A. Findings
0. Used for disease diagnosis
1. Better understanding of basic biology
2. There are far fewer genes in the human genome than previously
predicted.
3. Each gene can be alternatively spliced to code for several proteins.
Developments in genome sequencing have led to new fields in biology.
0. Genomics
. The comparison of genomes from different species
a. Identifies species evolutionary relatedness (gene
similarities)
1. Transcriptomics
. Examines when, where and how much mRNA for a given gene is
made.
a. Proteomics Examines the proteins that are predicted from the DNA
sequence.