Chapter 10 Flashcards
The first scientists to propose that DNA was a double-stranded helix were
Watson and Crick
Describe DNA
It is made up of nucleotides; sugar and phosphate groups are identical in all nucleotides; each full turn of a helix holds ten nucleotide pairs
The double-ring nitrogenous bases include or are called
purines
Bases complementary to adenine and guanine in DNA are respectively
Thymine and cytosine
Base-pairing rules dicate that a strand of DNA with the base sequence of ATCGTCAATC will form an opposite bs sequence of
TAGCAGTTAG
Nitrogenous bases form ___ bonds with each other to hold complementary DNA strands together.
Hydrogen
If the percentage of thymine on a DNA strand is 40%, what will the percentage of guanine be?
10%
What is the main purpose of DNA replication in cells?
to copy genetic information for cell division
In DNA replication, the enzyme ___ works to separate the H bonds and the strands
Helicase
In DNA replication, complementary bases are added by the enzyme ___.
DNA polymerase
As DNA separates for replicaation, the Y-shaped region that results is called what?
a replication fork
The end result of DNA replication without mutation is what?
two identical and separate DNA molecules
The enzyme that later joins the gaps in the newly copied strand of DNA is what?
DNA ligase
DNA replication in prokaryotes takes place in/on the what?
Cytoplasm
Newly synthesized DNA base pairs in most organisms are proofed and repaired by what enzyme?
DNA polymerase
Thymine dimers are two thymine bases linked together by ___ bond.
Covalent
A segment of DNA that is located on a chromosome and codes for a herditary characteristic is a what?
Gene
The construction of an RNA template from DNA is called what?
transcription
What is RNA?
A nucleic acid made up of ribose, phosphate, and nitrogenous bases
Which molecule bonds to a specific amino acid?
tRNA
What are the three major types of RNA?
ribosomal, transfer, messenger
The specific nucleotide sequence on teh DNA where transcription is initiated is called the what?
promoter
A specific sequence of nucleotides that marks the end of a genre is called what?
a termination signal
In eukaryotic cells, DNA replication takes place where?
at many points on and in both directions of a DNA strand
If a DNA strand had the basses ATTACGCCA, its transcribed RNA strand would contain the bases
UAAUGCGGU
Amino acids are assembled based on instructions encoded in teh sequence of necleotides on the
mRNA
A specific squence of three nucleic acids on an mRNA that code for an amino acid are called a what?
codon
The start codon AUG that always codes for the beginning of transcription is the code for what?
methionine
Amino acids are joined to one another by which type of bond?
peptide
How many different amino acids must be present for protein synthesis?
20
translation takes place in/on the what?
ribosome
An anticodon AUG would look for the codon ___ to bind to?
UAC
The newly made polypeptide falls off when the ribosome reaches what?
the stop codon
Describe translation
Several ribosomes can be translating a strand of mRNA at one time; in prokaryotes, translation and transcription can occur simultaneously; a new ribosome begins translating as soon as the preceding ribosome has moved aside
