Gene Expression Vocab Quiz Flashcards
(32 cards)
What does a double helix look like in DNA
Two strands of DNA wind around each other like a twisted
ladder. The strands are complementary —they fit together and are the opposite of each other.
The small units, or monomers, that make
up DNA are called ____
Nucleotides
The base pairing rule (Similar to Chargaff’s rule)
Thymine (T) always pairs with adenine (A), and cytosine (C) always pairs with guanine (G) (Chargaff’s rule is that they equal each other)
Replication
Process by which DNA is copied during the S phase of cell cycle
DNA polymerase
An enzyme that catalyzes the formation of the DNA molecule
The main difference between the four nucleotides that make up DNA is that they have different
Nitrogenous bases
In eukaryotic cells, DNA replication takes place in the
Nucleus
When new DNA molecules are formed, almost all errors are detected and fixed by
DNA polymerase
Three parts of a nucleotide
A phosphate group, a ring-shaped sugar called
deoxyribose, and a nitrogen-containing base
Steps of replication
- A DNA molecule unzips as nucleotide base pairs separate. Replication begins on both strands of the molecule at the same time
2. Each existing strand of the DNA molecule is a template for a new strand. Free-floating nucleotides pair up with the exposed bases on each template strand. DNA polymerases bond these nucleotides together to form the new strands.
3. Two identical double-stranded DNA molecules result from
replication. DNA replication is semiconservative. That is, each
DNA molecule contains an original strand and one new strand.
Central dogma of biology
The central dogma describes the flow of information from DNA to RNA to proteins. It involves three major processes
1. Replication, as you just learned, copies DNA (blue arrow).
2. Transcription converts a DNA message into an intermediate molecule, called RNA (red arrow).
3. Translation interprets an RNA message into a string of amino acids, called a polypeptide. Either a single polypeptide or many polypeptides working together make up a protein (green arrow).
RNA
A chain of nucleotides, each made of a sugar, a phosphate group, and a nitrogen-containing base. It is a temporary copy of DNA that is used and then destroyed.
Transcription
The process of copying a sequence of DNA to produce a
complementary strand of RNA
RNA polymerases
Enzymes that bond nucleotides together in a chain to make
a new RNA molecule.
mRNA
An intermediate message that is translated to
form a protein.
rRNA
Forms part of ribosomes, a cell’s protein factories.
tRNA
Brings amino acids from the cytoplasm to a ribosome
to help make the growing protein.
Translation
The process that converts, or translates, an mRNA message into a
polypeptide
Stop codons
Signal the end of an amino acid chain
Start codons
Signal the start of translation and the amino acid methionine
Anticodon
A set of three nucleotides that is complementary
to an mRNA codon
What is different about the bases of RNA
Instead of Thymine, Uracil is paired with Adenine.
How many amino acids are used to make up all of the proteins in the human body
20
Codon
A three-nucleotide sequence that codes
for an amino acid
