Intro Part 2 Flashcards
(almost) all inheritance is based on____: the sequence of _________encodes all instructions needed to build and maintain an organism.
DNA
ACGT nucleotides
A________ is a single DNA molecule together with other molecules (proteins and RNA) needed to support and read the DNA.
chromosome
A_____ is a specific region of a chromosome that codes for a single_______ (linear chain of amino acids).
gene
polypeptide
_______are composed of one or more polypeptides, plus in some cases other small helper molecules (co-factors)._____ do most of the work of the cell.
Proteins
Genes are expressed in a 2 step process:
Transcription
Translation
T or F
All cells in the body have the same DNA, but different genes are expressed in different cells and under different conditions.
True
Genes often have several_____: the same gene in the same chromosomal location, but with minor nucleotide changes that yield slightly different proteins.
alleles
For a given gene, many different alleles can exist in a population (members of the same species), but an individual diploid organism can have___ alleles at most:________
2
one from each parent.
________= having 2 copies of each gene and each chromosome.
Diploid
(where the mitotic spindle attaches)
centromere
(special structures on the ends of chromosomes)
telomeres
(where copying of DNA starts)
origins of replication
(non-functional, mutated copies of genes)
pseudogenes
(intranuclear parasites)
transposable elements a.k.a. transposons
Eubacteria and Archaea. Usually unicellular.
Prokaryotes
No internal membrane-bound compartments: DNA floats free in the cytoplasm.
Prokaryotes
1 circular chromosome (plus optional plasmids, which are also circular)
Prokaryotes
reproduction usually asexual
Prokaryotes
sexual processes (mixing DNA from 2 individuals) occur, but with unequal contributions from the 2 partners
Prokaryotes
transcription and translation simultaneous
Prokaryotes
Plants, animals, fungi, protists. Often multicellular.
Eukaryotes
DNA contained within a membrane-bound nucleus.
Eukaryotes
linear chromosomes (usually more than 1)
Eukaryotes
careful division of chromosomes in cell division: mitosis and meiosis
Eukaryotes
transcription separated from translation
Eukaryotes
sexual reproduction: 2 partners contribute equally to offspring
Eukaryotes
life cycle: alternation of haploid and diploid phases (i.e. 1 vs. 2 copies of each gene and chromosome)
Eukaryotes
which are any change in the DNA base sequence, occur constantly in all cells and organisms.
Offspring rarely get a perfect copy of the DNA from its parents.
Mutations
mutations are rare: about__ DNA base change per____ bases each cell generation.
1
109
Humans have about 3 x 109 bases and E. coli bacteria have about ______ bases
4 x 106
: the ability to survive and reproduce. An individual’s _____ is affected by its genes.
Fitness
__________: more fit individuals tend to increase their numbers each generation, at the expense of less fit individuals.
Alleles that confer higher fitness tend to take over in the population, causing a loss of less fit genes.
Natural selection
________changes, new species, are thought to usually occur in small isolated populations, where they don’t get swamped out or out-competed by the “normal” individuals.
Large scale
