BIOL 1010 Lecture Notes - Lecture 8: Soil Ph, Mitosis, Meiosis
Mitosis & Meiosis
October 7, 2014
Genetics – study of the inheritance of observable traits from one generation to the
next, and their affect on populations and species
Molecular Biology – study of the molecular processes involved in the transfer of
genetic information from genotype to phenotype of an organism
The action of many genes is influenced by the environment including its:
• Soil acidity or type
• Temperature
• Location
Genotype determines the phenotype.
Genotype – an organism’s genetic makeup; genetic information contained in genes
Phenotype – an organism’s physical and biochemical traits
Structure of the DNA Molecule
• Double stranded
• Bases (Adenine, Thymine, Cytosine, and Guanine) connected by hydrogen
bonds
• Forms a double helix
Chromosome Structure
Chromosomes are long strands of DNA
O
–O
O
OH
P
H2C
O
–O
O
O
P
H2C
O
–O
O
O
P
H2C
O
–O
O
O
P
O
OH
O
O
O
T
A
C
G
C
A
T
O
O
O
O
OH
CH2
O
O–
O
O
P
CH2
O
O–
O
O
P
CH2
O
O–
O
O
P
CH2
O
O–
O
O
P
5 end
Hydrogen bond
3 end
5 end
3 end
C
T
A
A
T
C
G
G
C
A
T
C
G
A
T
A
T
A
T
T
A
C
T
A
0.34 nm
3.4 nm
(a) Key features of DNA structure
(b) Partial chemical structure
(c) Space-filling model
G
1 nm
G
H2C
find more resources at oneclass.com
find more resources at oneclass.com
• Looks like a rod-shaped structure
• Ends are called telomeres
• Constricted region of the chromosome is called the centromere
• Homologous chromosomes are pairs of chromosomes with the same size
and shape
Human Karyotype – image displaying the chromosomes in the cell
• Humans have 23 pairs of homologous chromosomes
• Humans have sex chromosome X and Y which determine the sex
o X and Y have different sets of genes and are different shapes/sizes
o These chromosomes are still homologous chromosomes
The number of chromosomes differ from species to species, but are always in
multiples of two (diploid).
Chromosomes consist of DNA and Proteins:
• DNA is complexed with proteins called histones
• DNA and protein form chromatin
• Several conformations of chromatin exist in the nucleus of living cells
Hierarchical Structure of a Chromosome:
• 10 nm fiber (beads-on-a-string)
• 20 nm fiber (the solenoid)
• Chromosome looped-domains
• Metaphase chromosome
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
October 7, 2014 next, and their affect on populations and species. Genetics study of the inheritance of observable traits from one generation to the. Molecular biology study of the molecular processes involved in the transfer of genetic information from genotype to phenotype of an organism. The action of many genes is influenced by the environment including its: soil acidity or type, temperature, location. Genotype an organism"s genetic makeup; genetic information contained in genes. Phenotype an organism"s physical and biochemical traits. Structure of the dna molecule (c) space-filling model. 3. 4 nm: double stranded, bases (adenine, thymine, cytosine, and guanine) connected by hydrogen (a) key features of dna structure (b) partial chemical structure bonds, forms a double helix. Chromosomes are long strands of dna: looks like a rod-shaped structure, ends are called telomeres, constricted region of the chromosome is called the centromere, homologous chromosomes are pairs of chromosomes with the same size and shape.
