Introduction to Genetics Flashcards
Transmission genetics
Transfer of genetic information from parents to offspring; understand and predict how traits are inherited
Molecular genetics
deals w/ DNA and the genome; understanding gene structure, expression and function; Central Dogma
What is the genetic material in eukaryotes and prokaryotes? What is the genetic material in some viruses?
Eukaryotes and prokaryotes: DNA
Some viruses: RNA
Genome
an organism’s full DNA sequence, or the DNA or RNA sequence of a virus
What is DNA composed of and look like?
two chains each made of nucleotides composed of a deoxyribose sugar, a phosphate group, and a base; a double helix
What are the four bases in DNA?
Adenine, Thymine, Guanine, and Cytosine
What base is replaced in RNA and what is it called?
In RNA, Uracil replaces Thymine
Genes
specific base sequences passing traits from parents to offspring
How is genetic material in cells organized?
into chromosomes
What is the difference between how DNA is organized in prokaryotes and eukaryotes?
In prokaryotes, DNA is in a singular, circular chromosome.
In eukaryotes, DNA is either in the form of chromosome in a nucleus or in a circular molecule in an organelle.
Endosymbiosis theory
Organelles appeared from prokaryotes; Ex: mitochondria and chloroplast
Chromosome
composed of DNA and protein; circular in prokaryotes and linear in eukaryotes
Centromere
constricted part of a chromosome that holds together two chromatids
Nucleosomes
DNA packaged efficiently in a chromosome, coiled around molecular spools
Each nucleosome is composed of eight proteins called?
Histones
Chromatin
DNA + associating nucleosomes
Ploidy
number of sets of chromosomes
N
chromosome set
1N
1 set of chromosomes; haploid organisms have this
2N
2 sets of chromosomes; diploid organisms have this
Do haploid or diploid organisms have homologous pairs of chromosomes?
Diploid; 2 versions of each chromosome, 1 from each parent
How many chromosomes do the human species have? How many pairs of autosomes and how many pairs of sex-determining chromosomes do humans have?
46 total chromosomes, 22 pairs of autosomes and 1 pair of sex-determining chromosomes
Diploscapter pachys
a worm; “a single chromosome”; hasn’t had sex in 18 million yrs
Oxytricha trifallax
cilliate; “16,000 chromosomes”; organism that builds itself a new genome every time it has sex
What are the two examples of organisms that are polyploid?
Strawberries and salamanders
Polyploid
more than 2 sets of chromosomes
How much data does a strawberry store?
200 Terabytes
Central Dogma
transfer of instructions stored in DNA (genotype) into proteins that perform physical action and make physical form (phenotype)
What are the steps to Central Dogma?
- DNA replication
- Transcription (DNA ->RNA)
- Translation (RNA->proteins)
Reverse transcription
cDNA is made from a RNA template; cDNA has no introns compared to regular DNA
Population genetics
Change in genetic information among individuals over generations; understand and predict trait/gene evolution within populations
Quantitative genetics
deals w/ quantitative traits, which are phenotypes that vary continuously (such as height or mass)
What are the four sources of variation in DNA?
Mutations, recombination, selection, epigenetics
Mutations
heritable changes in genetic material
Recombination
exchange of genetic material; produced by enzymes that cut and rejoin DNA molecules
Selection
favoring particular gene combinations in a given environment
Epigenetics
changes in phenotype in the absence of any underlying change in the DNA sequence
Genetic maps
sites of genes (loci) on chromosomes, and genetic distances between them calculated from recombination in experimental crosses; show whether genes w/ related functions are on the same chromosome; useful in cloning and genome sequencing
Desirable qualities for an experimental organism (model organism) include:
- well-known genetic history
- short life cycle (generations can be studied in little time)
- large number of offspring per mating
- ease of growing and handling
- marked genetic variation