GTS 161 SU1
STUDY UNIT 1: CHROMOSOMES AND CELLULAR
REPRODUCTION
(4 lectures)
STUDY MATERIAL: Pierce Chapter 2 (p 17-46)
KEY CONCEPTS: Pierce p 40-41
TERMINOLOGY: Pierce p 41
*Have to use the textbook often
Untitled Attachment
LEARNING OUTCOMES
After completing the study unit, you should be able to:
• Compare the basic structure of prokaryotic and eukaryotic cells.
• Apply the terminology used to describe chromosome morphology and chromosome
numbers.
• Describe the cell cycle and check points, and understand where cell division fits into the
cycle.
• Describe the processes of mitosis and meiosis in detail.
• Name the cells that are involved in mitosis and meiosis.
• Compare the different aims of mitosis and meiosis and describe how these aims are
accomplished.
• Discuss and compare the mechanisms whereby genetic variation is generated during
gamete formation.
• List the specific terminology applicable to gamete formation in males and females in
animals.
Lecture 1.1
• Compare the basic structure and composition of prokaryotic and eukaryotic cells
1
, Prokaryotes Eukaryotes
Unicellular, no compartmentalised cell Can be unicellular or multicellular, with
structure compartmentalised cell structure
Made up of eubacteria ("true bacteria") Genetic material is surrounded in a
and archaea ("ancient bacteria") nuclear envelope to form a nucleus
DNA is closely associated with histones
DNA does not exist in highly ordered to form chromatin and sometimes tightly
and packed arrangement - free inside packed chromosomes
cytoplasm (DNA in eukaryotes always associated
with proteins called histones)
Viruses are neither prokaryotic or eukaryotic, and can only reproduce within host cells.
For cells to reproduce successfully:
1. Genetic information must be copied (!)
2. The copies of genetic info. must be separated from each other
2
, 3. The cell must divide
Prokaryotic cell reproduction: binary
Eukaryotic cell production
fission
• Simple division - separation of
replicated circular chromosome
• One origin of replication
• High rate of replication
Cell division more complex with
eukaryotes.
*Link concepts of DNA, genes, and
chromosomes and how they divide to
give two identical cells for mitosis or
genetically unique for meiosis.
• Distinguish between diploid and haploid
Eukaryotic chromosomes:
• Every species has specific number of chromosomes per cell (2n number - somatic
cells) - e.g. 46 in humans. (*Somatic cells are body cells - fixed number of
chromosomes per species. Number is not relevant to complexity of organisms.)
• Most eukaryotic cells are diploid - carry two full sets of chromosomes (or 2 copies
of every chromosome). One set inherited paternally (from father), other maternally
(from mother).
• In a diploid cell, chromosomes usually exist as homologous pairs or homologs.
• Diploid organism has 2 sets of chromosomes organised as homologous pairs.
Homologous chromosomes are alike in size and structure, and carry genetic
information for the same set of hereditary characteristics. They can differ in terms
of alleles for a specific gene.
3
, Above picture is a karyotype - shows the chromosomes.
Paired based on size and shape, centromere position etc. Carry the same genes in the
same place.
• Distinguish between DNA, chromatin, chromosome, chromatid, homolog
Chromosome structure: (criteria for a DNA molecule to act as a chromosome)
• An unreplicated chromosome consists of a single molecule of dsDNA (double
stranded DNA).
• Packaged with histone proteins inside nucleus (=chromatin).
• Elements of functional chromosome = centromere (attachment point for spindle
microtubules); telomeres (tips of a linear chromosome); origins of replication
(where DNA replication starts)
4
STUDY UNIT 1: CHROMOSOMES AND CELLULAR
REPRODUCTION
(4 lectures)
STUDY MATERIAL: Pierce Chapter 2 (p 17-46)
KEY CONCEPTS: Pierce p 40-41
TERMINOLOGY: Pierce p 41
*Have to use the textbook often
Untitled Attachment
LEARNING OUTCOMES
After completing the study unit, you should be able to:
• Compare the basic structure of prokaryotic and eukaryotic cells.
• Apply the terminology used to describe chromosome morphology and chromosome
numbers.
• Describe the cell cycle and check points, and understand where cell division fits into the
cycle.
• Describe the processes of mitosis and meiosis in detail.
• Name the cells that are involved in mitosis and meiosis.
• Compare the different aims of mitosis and meiosis and describe how these aims are
accomplished.
• Discuss and compare the mechanisms whereby genetic variation is generated during
gamete formation.
• List the specific terminology applicable to gamete formation in males and females in
animals.
Lecture 1.1
• Compare the basic structure and composition of prokaryotic and eukaryotic cells
1
, Prokaryotes Eukaryotes
Unicellular, no compartmentalised cell Can be unicellular or multicellular, with
structure compartmentalised cell structure
Made up of eubacteria ("true bacteria") Genetic material is surrounded in a
and archaea ("ancient bacteria") nuclear envelope to form a nucleus
DNA is closely associated with histones
DNA does not exist in highly ordered to form chromatin and sometimes tightly
and packed arrangement - free inside packed chromosomes
cytoplasm (DNA in eukaryotes always associated
with proteins called histones)
Viruses are neither prokaryotic or eukaryotic, and can only reproduce within host cells.
For cells to reproduce successfully:
1. Genetic information must be copied (!)
2. The copies of genetic info. must be separated from each other
2
, 3. The cell must divide
Prokaryotic cell reproduction: binary
Eukaryotic cell production
fission
• Simple division - separation of
replicated circular chromosome
• One origin of replication
• High rate of replication
Cell division more complex with
eukaryotes.
*Link concepts of DNA, genes, and
chromosomes and how they divide to
give two identical cells for mitosis or
genetically unique for meiosis.
• Distinguish between diploid and haploid
Eukaryotic chromosomes:
• Every species has specific number of chromosomes per cell (2n number - somatic
cells) - e.g. 46 in humans. (*Somatic cells are body cells - fixed number of
chromosomes per species. Number is not relevant to complexity of organisms.)
• Most eukaryotic cells are diploid - carry two full sets of chromosomes (or 2 copies
of every chromosome). One set inherited paternally (from father), other maternally
(from mother).
• In a diploid cell, chromosomes usually exist as homologous pairs or homologs.
• Diploid organism has 2 sets of chromosomes organised as homologous pairs.
Homologous chromosomes are alike in size and structure, and carry genetic
information for the same set of hereditary characteristics. They can differ in terms
of alleles for a specific gene.
3
, Above picture is a karyotype - shows the chromosomes.
Paired based on size and shape, centromere position etc. Carry the same genes in the
same place.
• Distinguish between DNA, chromatin, chromosome, chromatid, homolog
Chromosome structure: (criteria for a DNA molecule to act as a chromosome)
• An unreplicated chromosome consists of a single molecule of dsDNA (double
stranded DNA).
• Packaged with histone proteins inside nucleus (=chromatin).
• Elements of functional chromosome = centromere (attachment point for spindle
microtubules); telomeres (tips of a linear chromosome); origins of replication
(where DNA replication starts)
4
