lecture exam 3 Flashcards
process by which a gene produces its product and the product carries out its function
gene expression
A natural process in which a nucleic acid molecule (usually DNA but can be RNA) is broken and then joined to a different molecule; a result of crossing‐over.
gene recombination
genetic information can be transferred vertically to the next generations of cells
gene replication
in each new DNA double helix, one strand is from the original molecule, and one strand is new
semi-conservative replication
Developed the double helix model of DNA.
Watson and Crick
purines (double ring)
Adenine and Guanine
Guanine and cytosine make ____ H bonds
Adenine and thymine make ____ H bonds
3 / 2
in transcription, the ___ strand contains info to make RNA and is transcribed
master
type of RNA that combines with proteins to form ribosomes
rRNA
An RNA molecule that carries amino acid to the ribosome in translation
tRNA
An RNA molecule that helps decode an mRNA sequence into a protein
tRNA
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and carries message to translate protein
mRNA
- rRNA
- mRNA
- tRNA
types of RNA that is made in transcription
the ribosome demands ____ and _____
rRNA / protein
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
Codon
group of three bases on a tRNA molecule that is complementary to an mRNA codon
Anticodon
There are only codons in _______
mRNA
start codon
Methianine
specific region of a gene where RNA polymerase can bind and begin transcription
Promoter
the enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template
RNA polymerase / transcriptase
A Y-shaped region on a replicating DNA molecule where new strands are growing.
replication fork
change in the DNA base sequence
Mutations
genetic composition of an organism
Genotype
physical / expressed characteristics of an organism
Phenotype
random changes that occur naturally in DNA that occur during cell division
spontaneous mutations
refers to those mutations in the DNA induced by a chemical or physical agent
induced mutations
A mutation that changes a single nucleotide and genotype, but does not change the amino acid created or phenotype.
MOST COMMON TYPE
silent mutation
A base-pair substitution that results in a codon that codes for a different amino acid.
missense mutation
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.
nonsense mutation
protein cannot be made because it cuts the mRNA short
why is a nonsense mutation lethal?
the mutation that shifts the “reading” frame of the genetic message by removing or adding a base
frameshift mutation
the genes code for enzymes that catalyze reactions that result in characteristics
Genetics and metabolism are tied together by the fact that :
A person has brown eyes because:
enzymes catalyze reactions that produce products that are brown
radiation-x-rays, UV light
examples of physical mutagens
- adjacent thymines cross link and create a thymine dimer
- endonuclease cuts the dimer and exonuclease removes the dimer
- DNA polymerase fills in the gap from the removed dimer
- DNA ligase seals the remaining gap
what happens when UV light hits a gene?
pesticides, natural plant alkaloids, tobacco smoke, pollutants
examples of chemical mutagens
Marijuana is not a big ____ cancer contributor
lung
what is the greatest fear that teenage girls have about smoking?
wrinkles
what is the greatest fear that teenage boys have about smoking?
erectile dysfunction
A ___ ___ in specific genes in a single cell will initiate cancer
double mutation (DM)
a mutation that happens because it has more target to mutate from than a single mutation
double mutation
Lung cancer takes _____ to develop
20-30 years
When one is suffering from secondhand smoke, they still take in ____ and ____
inducers / promoters
the transfer of genetic material in bacteria that occurs in one direction
one way gene transfer
transformation
conjugation
transduction
types of one way gene transfer in bacteria
one organism must die and release DNA to the environment and DNA is taken up by a cell that is competent and expresses new characteristics
Transformation
an experiment carried out by Griffith using the heat-killed bacteria in mice to discover that a factor in heat-killed, disease-causing bacteria can “transform” harmless bacteria into ones that can cause disease
Griffith’s experiment
In genetic transformation in bacteria, the donor cell has to be ____ and recipient cell has to be _____
dead / alive
what bacteria does not perform genetic transformation?
E. coli
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
Conjugation
used for conjugation and randomly touches cells and pulls them into contact to create a mating bridge between the bacterial cells
sex pilus
F+ cell is the “___” cell
F- cell is the “___” cell
male (has pilus)
female (does not have pilus)
gram-positive conjugation was identified in _____
gram-positive conjugation has no ____ ____
gram-positive conjugation uses sex _____
Streptococci
sex pilus
pheromones
chemical signals released by an animal that influence the sexual behavior or physiological state of other individuals of the same species
sex pheromones
sex pheromones are expelled in ____
sweat
DNA is transferred from a donor cell to a recipient via a bacteriophage
Transduction in bacteria