What are Mendel's 3 main points he contributed to genetics?
1. Demonstrated traits are passed from parent to offspring in
predictable ways
2. Each trait is controlled by
pair of genes
(unit factors)
3. Gene pairs separate from each other during gamete formation
The branch of biology concerned with the study of
heredity and variation
Genetics
A condition in which each chromosome
exists in pairs
having two of each chromosome
Diploid (2n)
Members of each species have a characteristic number of chromosomes
Diploid number
Cell or an organism having
one member of each pair of homologous chromosomes.
Also referred to as the
gametic chromosome number.
Haploid (n)
What is the diploid number for humans?
46
Order of display
Karyotype
These individuals noted genes and chromosomes have similar properties and behaviors; linking the observed behavior of chromosomes to Mendel's postulates for inheritance
- both exist in pairs
-Members of the pair segregate during gamete formation
as well a
Sutton & Boveri
Inherited traits are controlled by genes residing on chromosomes faithfully transmitted through gametes, maintaining genetic continuity from generation to generation.
Chromosome theory of inheritance
Any heritable change and the source of all genetic variation.
Mutation
Alternative forms of a gene
Allele
Fundamental term
Observable features of an organism (visible result)
Phenotype
Fundamental term
The set of alleles for a given gene carried by an organism
Genotype
Passed on one generation to the next
Heritable
These individuals performed the key experiment showing DNA was genetic material
bacteriophage
(not protein) as well as conducting a
key historical experiment in genetics
in 1944
Avery, MacCloud & McCarty
What structure does DNA form?
double helix structure
DNA is mad e of
2 strands
composed of?
Nucleotides
DNA consists of four nucleotides with one of four nitrogenous bases
A, T, G, C
In DNA nitrogenous bases
A & T
compose what amino acid?
sugar
deoxyribose
In DNA nitrogenous bases
C & G
produce what amino acid?
Nucleotide
In DNA nitrogenous bases
G & C
produce what amino acid?
Phosphate
Complementary base pairs
T & A
in DNA produce?
Thymine-adenine
Nucleotide complementary is the basis for
gene expression; which
complementarity is the key to these processes
Transcription =
DNA > RNA
Translation =
mRNA > protein
The deoxynucleotide triplets that encode the 20 amino acids or specify termination of translation
Genetic code
Were key discovery for development of recombinant DNA techniques
Restriction enzymes
What do enzymes serve as?
Biological catalysts
Protein's structure and function ultimately derived from
genetic code in DNA
Set of techniques used to make a large number of copies of DNA sequences
DNA cloning
Cloning allows for what to be obtained?
large quantities of specific DNA
The complete haploid content of DNA specific to an organism
Genome
The used of genetically modified organisms or their products
Biotechnology
An organism whose genome has been modified by the
introduction of external DNA sequences into the germ line
Transgenic animals
The study of genomes. Involves sequencing genomes and studying the structure, function and evolution of genes and genomes
Genomics
Examines the set of proteins in a cell under a given set of conditions.
- Also modifications, location, interactions
Proteomics
A subfield of information technology that deals with the massive amounts of data within genomics and proteomics
Bioinformatics
Most common used model organisms:
-
E.coli
-
yeast
-
Drosophila
-
C. elegans
-
mouse
-
zebrafish
-
Arabidopsis thaliana
Why do geneticists use these models?
The genetic mechanisms are often the same or similar in humans or human diseases
What properties make for a good model organism?
-
Easy to breed
-
Short life cycle
-
Straightforward genetic analysis
-
Produce large numbers of offspring
Two processes involved in
maintaining genetic continuity
Mitosis & Meiosis
Results in the production of two cells, each with the
same number of chromosomes as the parent cell
Mitosis
Reduces the genetic content
and the chromosome number precisely in half. Results in the production of sex cells, called gametes or spores
Meiosis
In these organisms genetic information found in
single, long circular DNA molecule
found in enclosed region called nucleoid
Prokaryotes
DNA in these organisms are not compacted
Prokaryotes
These organisms are not associated with proteins to the extent as eukaryotes
Prokaryotes
No distinct nucleolus
Prokaryotes
Constricted region with a chromosome
Centromere
Shorter arm of chromosome (petite)
p arm
Longer arm of chromosome
q arm
Chromosomes exist in pairs, the members of each pair are referred to as
Homologous chromosomes
Number of chromosomes equal to one half the diploid number
Haploid number (n)
How are homologous chromosomes identical?
position of genes
The site or place on a chromosome where a particular gene is located
Locus (loci)
Inheritance from 2 parents
Biparental inheritance
These organisms have 2 copies of every gene
Diploid organisms
What are the roles of mitosis?
- replacement of cells
- production of new cells
- asexual reproduction in single celled organisms
In single celled organisms, mitosis provides mechanism for
asexual reproduction
Single celled fertilized eggs of diploid organisms. Undergo development into multicellular organisms through mitotic division
Zygotes
Basis for
wound healing, replacement of lost cells
Mitosis
The process of
nuclear division
whereby the genetic material is partitioned into daughter cells
Karyokinesis
Cell division
Cytokinesis
The initial stage of the cell cycle, includes the interval between divisions
Interphase
Synthesis of DNA occurs prior to cell entering mitosis
S phase
Chromosomes are extended and uncoiled forming chromatids
Interphase
Periods of metabolic activity, growth and differentiation
G1 & G2
gapI and gapII
Mitosis averages how long?
1 hour and short period of the entire cell cycle
Chromosomes coil up and condense centrioles divide and move apart
Prophase
- Migration of pair of centrioles to opposite ends of cell
- Nuclear envelope breaks down
- Nucleolus disintegrates
- Chromatin
condenses
Mitosis
Prophase
The two genetically identical parts of each chromosome formed from single replicative event during
S phase
Sister chromatids
Chromosomes migrate to equatorial plane
Mitosis
Prometaphase & Metaphase
Period of chromosome movement
Prometaphase
Chromosomes aligned along metaphase plate
Metaphase
Multilayered plates of proteins associated with centromere
Kinetochore
Chromosomes are clearly double structures; centrioles reach the opposite poles; spindle fibers form
Prometaphase
Centromeres align on metaphase plate
Metaphase
Enzyme that degrades
...