Exam 3 (chapters 8, 9, 15, 20) Flashcards
Term for all genetic information in a cell:
genome
Term for segments of DNA that encode functional products, usually proteins:
genes
The ________ is a set of rules that determines how a nucleotide sequence is converted to an amino acid sequence of a protein.
genetic code
What are the four nitrogenous bases in DNA?
adenine, guanine, cytosine, thymine
What are the four nitrogenous bases in RNA?
adenine, cytosine, uracil, guanine
What two molecules make up chromosomes?
Each chromosome is made of protein and single molecule of DNA
How is the alteration of bacterial genes and gene expression important?
Helps understanding of cause of disease, how to prevent disease and treatment, can be manipulated for human benefit
List the chain of events described by central dogma:
DNA, mRNA, protein, function
Term for genetic makeup of an organism:
genotype
Term for expression of the genes (physical appearance of the organism in response to the genes expressed):
phenotype
Bacteria usually have what type of chromosome…made of ____ and _____?
single circular chromosome; single circular molecule of DNA; proteins
_____ are structures containing DNA that physically carry hereditary information.
chromosomes
What forms the basic structural unit of DNA?
nucleotides
What is a nucleotide made of?
nitrogenous base, pentose sugar, phosphate
What determines the genetic code?
the order of the nitrogen containing bases (contain the genetic instructions of the organism)
DNA forms a ______. The backbone consists of_____.
double helix; dexoxyribose-phosphate
Two strands of nucleotides are held together by ____ between A-_ and C-_.
hydrogen bonds; T; G
During DNA _____ one strand serves as a template for the production of a second strand.
replication
What has to happen to the DNA strands for replication to occur?
the strands have to separate
T/F DNA replication is more than 99% accurate
True
Why is replication highly accurate?
because of the proofreading capability of DNA polymerase (able to fix mistakes and proofreads as each nucleotide is added)
Most bacterial DNA replication is _______.
bidirectional (because it is a circular chromosome)
When does DNA replication occur in the life of a cell?
before cell division
How do bacteria divide?
binary fission
What two processes are involved in gene expression?
transcription and translation
When the information stored in our DNA is converted into instructions for making proteins or other molecules, it is called:
gene expression
Term for the synthesis of a complementary mRNA strand from a DNA template:
transcription (DNA > RNA)
Transcription begins when _____ binds to the ____ promoter sequence on DNA.
RNA polymerase; promoter
Transcription proceeds in the __’ to __’ direction.
5;3
T/F only one of the two DNA strands is transcribed during transcription
True
Transcription stops when it reaches the _____ sequence on DNA.
terminator
Term for the process where mRNA is translated into the “language” of proteins:
translation (RNA > PROTEIN)
What does transcription produce?
mRNA
Where does transcription take place in bacteria?
cytoplasm (because prokaryotes lack a membrane bound nucleus)
Where does transcription take place in eukaryotes?
membrane bound nucleus
What are groups of three mRNA nucleotides that code for a particular amino acid?
codons
How many codons encode the 20 amino acids:
64
Type of RNA that is an integral part of ribosomes:
ribosomal RNA (rRNA)
Type of RNA that transports amino acids during protein synthesis:
transfer RNA (tRNA)
Type of RNA that carries coded information needed to make protein from DNA to ribosomes:
messenger RNA (mRNA)
What are the three types of RNA?
ribosomal, transfer, messenger
Components of ribonucleic acid:
single-stranded nucleotide, 5-carbon ribose sugar, uracil instead of thymine
What does the process of translation produce?
proteins
Protein synthesis is called ______.
translation
Where does translation take place in bacteria?
cytoplasm
Where does translation occur in eukaryotes?
outside the nucleus in the cytoplasm
The genetic code involves ______, meaning each amino acid is coded by several codons.
degeneracy
How many amino acids does a cell need to make all of its proteins?
20
How many codons are there in the genetic code?
64
How are amino acids joined?
peptide bonds
Translation of mRNA begins at the:
start codon (AUG)
Translation ends at:
nonsense codons (UAA, UAG, UGA)
T/F In bacteria, transcription and translation can happen simultaneously…is this true in eukaryotic cells?
True. But they cannot occur simultaneously in eukaryotic cells because transcription occurs in the membrane bound nucleus and translation occurs in the cytoplasm
Term for self-replicating circular pieces of DNA:
plasmids
What often codes for proteins that enhance the pathogenicity of a bacterium?
plasmids
_____ and ______ are genetic elements that exist outside of chromosomes:
plasmids; transposons
Can plasmids be replicated?
Yes, they can replicate independently
Can plasmids be passed on to the next generation of bacterial cells?
Yes: increases pathogenicity
What are the three types of plasmids?
conjugative, dissimilation, resistance factors (R factors)
What carries genes for sex pili and transfer of the plasmid?
conjugative plasmid (horizontal gene transfer)
What encodes enzymes for the catabolism of unusual compounds?
dissimilation plasmids