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67 Cards in this Set

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What does DNA stand for?
deoxyribonucleic acid
What is the study of molecular genetics based on?
The activity of deoxyribonucleic acid (DNA) and how this activity brings about the production of proteins in the cell.
What is the function of deoxyribonucleic acid (DNA)?
To relay inherited information to messenger RNA (mRNA).
What is the function of messenger RNA (mRNA)?
It codes for proteins.
What is the "Central Dogma" of molecular biology?
The flow of information from DNA to protein.
What two biochemists proposed a model for the structure of DNA in 1953 and later shared the Nobel Prize for their work in 1962?
James D. Watson and Francis H.C. Crick
The discovery of the structure of DNA allowed us to see how genes operate and how DNA can reproduce itself during mitosis. In addition to protein synthesis, what two fields of science did this discovery open?
Biotechnology and genetic engineering.
What are the two long strands that form a double helix in a molecule of DNA?
Nucleotide chains.
What three parts make up a nucleotide in a chain of DNA?
A nitrogenous base, a phosphate group, and a molecule of deoxyribose.
What are the two major types of nitrogenous bases that make up a nucleotide in a DNA chain?
Purines and pyrimidines.
What is a purine made up of?
Two fused rings of carbon and nitrogen atoms.
What is a pyrimidine made up of?
One ring of carbon and nitrogen atoms.
What are the two purine bases in DNA?
adenine (A) and guanine (G)
What are the two pyrimidine bases in DNA?
cytosine (C) and thymine (T)
Are purine and pyrimidine bases found in only one strand or both strands of the double helix of a DNA molecule?
Both strands of the double helix.
What is the phosphate group of a nucleotide of DNA derived from?
phosphoric acid
Are the chemical bonds that hold together the two strands in a double helix of a DNA molecule weak or strong?
weak
What is the function of a phosphate group in a nucleotide chain?
It connects deoxyribose molecules to one another.
What is deoxyribose made up of and how is it classified?
It is a five-carbon carbohydrate.
What are the purine and pyrimidine bases attached to on the nucleotide chains?
Molecules of deoxyribose.
How are the purine and pyrimidine bases arranged on the two strands of DNA?
They are opposite each other on the two strands.
What pyrimidine base is adenine (A) always opposite to and bind with on an opposing nucleotide chain?
thymine (T)
What pyrimidine base is guanine (G) always opposite to and bind with on an opposing nucleotide chain?
cytosine (C)
What is the principle of complementary base pairing?
The purine bases adenine (A) and guanine (G) always complement, or are paired and bind with, the pyrimidine bases thymine (T) and cytosine (C), respectively, on opposing nucleotide chains of DNA.
What pyrimidine base does adenine complement?
thymine
What pyrimidine base does guanine complement?
cytosine
What purine base does cytosine complement?
guanine
What purine base does thymine complement?
adenine
What enzyme joins nucleotide components to one another, forming a long strand of nucleotides?
DNA polymerase
How is DNA replicated?
Specialized enzymes pull apart, or "unzip", the DNA double helix, exposing purine and pyrimidine bases. These bases then attract their complementary bases. DNA polymerase joins the nucleotides to form a new nucleotide chain under the direction of the old strand of DNA. These two strands then join together to form a new double helix.
Why is DNA replication referred to as "semiconservative replication"?
Because an old strand of DNA remains a part of the new DNA double helix.
What two strands make up a newly replicated molecule of DNA?
An old strand of DNA and a newly-replicated, complementary strand of DNA.
In what direction does DNA polymerase join nucleotides on the leading strand during DNA replication?
5'-3'direction
What is the 3'-5' strand called during DNA replication?
The lagging strand.
How is the lagging strand synthesized during DNA replication?
In short segments in a 5'-3' direction (from the leading strand to the lagging strand).
What are the short strands of DNA produced along the lagging strand during replication called?
Okazaki fragments
What enzyme joins together Okazaki fragments during DNA replication?
DNA ligase
During what phase of the cell cycle does DNA replication occur?
S phase
Name three general functions of proteins.
As enzymes, as structural materials in cells, and in cellular activities.
What does RNA stand for?
ribonucleic acid
What is the function of RNA in protein synthesis?
It carries instructions from the nuclear DNA into the cytoplasm of a cell, where protein is synthesized.
What is the carbohydrate in RNA?
ribose
What pyrimidine does RNA contain rather than thymine in its DNA counterpart?
uracil (U)
What are the three types of RNA?
ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA)
What is the function of ribosomal RNA (rRNA)?
This RNA is used to manufacture ribosomes.
What do ribosomes consist of?
Ribosomes consist of ultramicroscopic particles of ribosomal RNA (rRNA) and protein.
What is the function of ribosomal RNA (rRNA)?
These are the chemical "workbenches" of the cell where amino acids are linked to one another to synthesize proteins.
What are the three types of RNA?
ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA)
Where are ribosomes found?
Along the membranes of the endoplasmic reticulum or in the cytoplasm of the cell.
Where is transfer RNA (tRNA) found in the cell?
In the cytoplasm.
Describe the way in which enzymes link tRNA molecules to amino acids. Is it highly ordered or very random?
Highly ordered. Each different type of amino acid has its own specific tRNA that delivers it to ribosomes for protein synthesis.
Where is messenger RNA synthesized?
In the nucleus at DNA molecules.
What is the function of messenger RNA?
It receives the genetic code from the DNA in the nucleus and carries the code into the cytoplasm.
What enzyme is used in the synthesis of mRNA, tRNA, and rRNA?
RNA polymerase
What is DNA?
Deoxyribonucleic acid: a double helix nucleotide molecule containing deoxyribose, nitrogenous base, and a phosphate group; contains the genetic information from which amino acids are determined.
What is DNA polymerase?
The enzyme that joins all the nucleotide components to one another to form a long strand of nucleotides.
What is DNA replication?
The process by which cells replicate or synthesize their DNA; takes place during S phase of the cell division cycle.
What is mRNA?
Messenger RNA (ribonucleic acid): the RNA molecules that receive the genetic code in the DNA and carry the code in the DNA into the cytoplasm where protein synthesis takes place.
What is a nitrogenous base?
The nitrogen-containing molecules that make up DNA and RNA molecules. Two major types are purines and pyrimidines.
What are nucleic acids?
Large molecules comprised of nucleotides.
What is a nucleotide?
The unit that makes up nucleic acid; contains a nitrogen base, a phosphate group, and a carbohydrate molecule.
What are ribosomes?
Organelle bodies that may be bound to the endoplasmic reticulum (ER) that are the sites of protein synthesis in eukaryotic cells; the bodies in which amino acids are bound together to form proteins.
What is RNA?
ribonucleic acid: a nucleic acid produced during transcription that is complementary to a DNA strand; similar to DNA in structure but contains the carbohydrate ribose and the pyrimidine uracil rather than thymine.
What is the S phase?
The phase within the cell division cycle in which DNA is replicated.
What is transcription?
The process in which a complementary strand of mRNA is synthesized according to the nitrogenous base code of DNA.
What is tRNA?
Transfer RNA (ribonucleic acid): RNA molecules in the cytoplasm of a cell that carry amino acids to the ribosomes for protein synthesis.
During transcription, how many strands of DNA serve as the template for RNA synthesis?
One strand. The other remains dormant.