Lecture 01: Intro to Genetics Flashcards
what is genetics?
the study of variation and heredity
what is variation?
similarities and differences among organisms
what is heredity?
how characteristics are transmitted thru generations
what does genetic information do?
- directs cellular function
- determines an organism’s external appearance
- link between generations in every species
In history: genes are particulate factors
Gregor Mendel
In history: discovery of nucleic
Friedrich Miescher
In history: chromosomes are hereditary units
Walter Sutton
In history: genes lie on chromosomes
Thomas Hunt Morgan
In history: chromosomes are linear arrays of genes
Alfred Sturtevant
In history: mutations are physical changes in genes
Hermann Muller
In history: recombination occurs by crossing over
Harriet Creighton and Barbara McClintock
In history: a gene codes for a protein
George Beadle and Edward Tatum
In history: DNA is the genetic material
Oswald Avery, Colin MacLeod, and Maclyn McCarty
In history: first protein sequenced
Frederick Sanger
In history: DNA is a double helix
James Watson, Francis Crick, and Rosalind Franklin
In history: DNA replicates semiconservatively
Matthew Meselson and Franklin Stahl
In history: genetic code is triplet
Marshall Nirenberg and Heinrich Matthaei
In history: DNA can be sequenced
Frederick Sanger, Allan Maxam, and Walter Gilbert
In history: Haemophilus influenzae genome sequenced
Institute of Genomic Research
In history: human genome sequenced
Human Genome Project
different fields of genetics
- transmission genetics
- cytogenetics
- molecular genetics
- population genetics
what is transmission genetics?
patterns of inheritance are determined thru planned breeding experiments
what is cytogenetics?
study of the cellular or physical basis of heredity (chromosomes)
what is molecular genetics?
characterization of the chemical nature of the genetic materials as well as the how the traits are expressed
what is population genetics?
describes the behavior of genes in large groups of individuals with passage of time
what are the methods of studying genetics?
- planned experimental breeding
- pedigree analysis
- statistical analysis
- twin study
- karyotyping
- DNA testing/ profiling
what is planned experimental breeding?
mating of individuals with contrasting traits
characteristics of a good test organism for genetic study
- observable traits
- can sexually reproduce
- controlled mating not within the bounds of ethical concerns
- short generation time
- produce large number of offspring
- easy to handle
what is pedigree analysis?
uses diagrams to show ancestral relationship and transmission genetics over several generations
what is statistical analysis?
- used in tandem with planned experimental breeding
- tests for significant difference in variations
what is twin study?
determines which plays a more significant role in the expression of a trait: heredity or environment
what is karyotyping?
- metaphase chromosomes are arranged according to size and centromere location
- detects chromosomal abberations
down syndrome has an extra chromosome in what chromosome number?
chromosome 21
what is DNA testing/ profiling?
detects differences at the molecular level
these are the discrete heritable units that are passed from parent to offspring
genes
what are alleles?
alternative forms of the same gene
where are alleles found?
in chromosomes
two types of alleles
dominant and recessive
it is the particular site in the chromosome where an allele is found
locus
these are the matched pair of chromosomes in a diploid cell
homologous chromosomes
it deals with the principles of variation and how it is inherited at the molecular level
molecular genetics
these composes chromosomes
DNA and histone proteins
shape of a prokaryotic DNA
circular
it is an irregularly shaped region within a prokaryotic cell that contains its genetic material
nucleoid
how are prokaryotic DNA packaged?
folded into a number of loops that are further condensed (twisting or supercoiling) held in place by RNA molecules with proteins
what comprises the eukaryotic nucleosome?
DNA and 8 histone molecules (2 of each: H2A, H2B, H3, and H4)
characteristics of a genetic material
- stable
- replicable
- translatable
- mutable
describe the serotype IIR in Griffith’s experiment
- rough colony morphology
- capsule is absent
- avirulent
describe the serotype IIIS in Griffith’s experiment
- smooth colony morphology
- capsule is present
- virulent
components of nucleotides
- pentose sugar backbone
- phosphate group
- nitrogen base
pyrimidine bases
- cytosine
- uracil
- thymine
purine base
- guanine
- adenine
how are nucleic acids connected to each other?
thru 3’ to 5’ phosphodiester bond
describe the strength of the H-bonds of pairs of nucleotides
- thymine and adenine: weak
- cytosine and guanine: strong
the heavy strand of 2 complementary strands contains 50% of what?
purines
the light strand of 2 complementary strands contains 50% of what?
pyrimidines
features of B-DNA
- right-handed double helix
- anti-parallel
- bases are flat structures
- ten base pairs per turn
- alternating major and minor grooves
T or F: prokaryotic transcription/ translation is uncoupled
F, it is coupled
in what stage of the cell cycle does replication happen?
S phase
what are the types of transcription RNA and their function?
- tRNA: carries amino acids
- rRNA: binds with proteins to form ribosomes
- mRNA: template for protein synthesis
- miRNA: regulates gene expression
T or F: nucleotide addition in transcription is done by DNA polymerase
F, it is RNA polymerase
T or F: transcription results to a single-stranded RNA
T
it is the strand wherein RNA is transcribed
antisense or template strand
T or F: transcribed RNA is identical to the coding strand
T
T or F: eubacteria uses several types of RNA polymerase for all types of RNA
F, uses only one
subunits involved in the polymerases of eukarya
- RNA pol I: 18S, 5.8S, 28S rRNA
- RNA pol II: precursor mRNA, miRNA
- RNA pol III: tRNA, 5S rRNA, miRNA
steps in transcription
- initiation
- elongation
- termination
it is the biosynthesis of amino acid sequence from an mRNA template
translation
what are the types of translation RNA?
- mRNA
- tRNA
- rRNA
it is a triplet of nucleotides that code for an amino acid
codon
activates tRNA in translation
aminoacyl tRNA synthetase
rRNA binds with _______ to form ribosomes
ribonucleoproteins
this is where mRNA is read and translated into protein
Ribosome
these comprises the large subunit of prokaryotic ribosomes
5S, 23S
these comprises the large subunit of eukaryotic ribosomes
5S, 5.8S, 28S
T or F: transcription and translation occur simultaneously in prokaryotes
T