Ch. 9 Study Guide Flashcards
Heredity
the transmission of an organism’s genome to the next generation by chromosomes
Genome
The sum total of genetic material carried within a cell (chromosomes/genes/DNA)
Gene
A site on a chromosome that provides information for a certain cell function-a DNA segment with the necessary code for a protein or an RNA molecule
Phenotype
The observable characteristics of an organism produced by the expression of its genetic potential
-includes any morphological and physiological traits
Genotype
The genetic makeup of an organism as inherited from parents- ultimately responsible for the phenotype
What is the central dogma of biology?
DNA –> RNA –> Protein
Is there any difference between the basic nature of genetic material in eukaryotes, prokaryotes, and viruses?
Genomes of cells are composed exclusively of DNA, but viruses contain either DNA or RNA as the principal genetic material
Eukaryotic chromosomes are DNA wrapped around histone proteins, while bacterial chromosomes are condensed and secured via a different protein
Bacteria have single, circular chromosomes
What kinds of monomers make up DNA, RNA, and proteins?
DNA and RNA are made up of nucleotides. Each have 4 types, (RNA has uracil instead of adenine)
Proteins are made up of amino acids. There are 20 kinds of amino acids
List three major differences between DNA and RNA structure
DNA has the nucleotide adenine instead of uracil.
DNA is a double-stranded molecule.
DNA has a deoxyribose sugar, not a ribose sugar
Describe elongation of replication
DNA polymerase adds nucleotides to the leading strand.
Primase enzyme adds Okizaki fragments of nucleotides to the lagging strand so that DNA Polymerase can begin working.
Describe termination in DNA replication
the fork reaches the termination site, disconnecting the new DNA strand
Describe initiation of DNA Replication
Helicase enzymes bind to DNA at Origin of Replication, untwist helix, and break bonds between 2 strands
Where is DNA replication initiated in bacteria?
Nucleoid
What does semiconservative replication mean?
The parent (template) DNA is retained in the final molecule
What does DNA polymerase do during DNA Replication?
Adds nucleotides to template strands
What does Primase do during DNA Replication?
Creates short stretches of nucleotides to lagging strands, allowing DNA Polymerase to synthesize DNA in the 3 to 5 direction
What does Helicase do during DNA Replication?
Unzips DNA template
What does Ligase do during DNA Replication?
Bonds okazaki fragments, chemically bonding then together
What does Gyrase do during DNA Replication?
Supercoils the replicated DNA back together
What does antiparallel mean when describing DNA?
the double helix’s strands run in opposite directions
How many replication forks are present during the replication of a bacterial chromosome?
Two
What does RNA polymerase bind to/recognize?
Promotor region
What is a codon?
a set of 3 nucleotides
Is the genetic code universal?
Yes (very few exceptions)
Why is the genetic code described as being degenerate but not ambiguous?
Degeneracy=redundancy: a particular amino acid can be coded for by more than one codon.
The genetic code is unambiguous because one codon codes for only one amino acid.
What types of RNA are required during translation?
mRNA
tRNA
rRNA
Describe the structure of bacterial ribosomes
rRNA + protein
large subunit: 50 S
small subunit: 30 S
Total bacterial ribosome: 70 S
What initiator tRNA is used by bacteria?
formyl methionine (start codon AUG)
How is translation terminated?
Ribosome reaches stop codon on mRNA (not necessarily the last codon)
