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DNA
Question | Answer |
---|---|
What are nucleic acids? | Nucleic acids are large polymers made up of smaller repeating units, or monomers. |
What are nucleic acid monomers called? | Nucleotides |
What are the four DNA nucleotides? | Adenine (A), guanine (G), thymine (T), and cytosine (C). |
What are the complimentary DNA nucleotide bases? | Guanine and Cytosine. Adenine and Thymine. |
What are the four RNA nucleotides? | Adenine (A), guanine (G), cytosine (C), uracil (U). |
What are the complimentary RNA nucleotide bases? | Guanine and Cytosine. Adenine and Uracil. |
How do scientists label the carbons in the sugar part of the backbone for both RNA and DNA? How do they label the phosphate group? | Scientists label the carbons in the sugar from 1' to 5' based on their position in the molecule. The phosphate group is attached to the sugar at the 5' carbon |
True or False: One sugar-phosphate chain runs in the 5' to 3' direction and the other runs in the 3' to 5' direction. | True. |
What are the two complimentary stands of DNA held together by? | Hydrogen bonds |
What shape does DNA take? | The two strands wind together to form a spiral shape called a double helix. |
What shape does RNA take? | RNA is single stranded, some RNA molecules form folded structures, and, like proteins, these folded RNA molecules perform various functions like catalyzing reactions and transporting molecules. |
What charge is the DNA phosphate in the backbone? | Negative. |
True or False: DNA is not a polar molecule, so it cannot be easily dissolved in water, but dissolves in non-polar solvents such as alcohol. | False. |
Where is DNA found in eukaryotic organisms? | In eukaryotic organisms, DNA is contained inside the cell nucleus. DNA is tightly coiled around proteins to form structures called chromosomes. |
What is gene expression? | The result of coding information determined by DNA |
Where is DNA found in prokaryotes? | The DNA of prokaryotes is usually arranged in a single circular chromosome that is located in an area called the nucleoid and may be loosely tethered to the cell membrane. |
True or false: Chromosome number does not directly relate to the complexity of organisms. | True. Ex: Humans have 23 pairs of chromosomes, or 46 total; a dog has a total of 78, and the adder's-tongue fern a total of 1,260! |
Where is genetic information located? | Genetic information is encoded in the order of nucleotide bases in DNA. |
What are "coding" segments called? What do they do? | Genes. Each gene codes for a different protein. An organism’s DNA contains the genes to code for all of the proteins that the organism needs to produce structures and carry out life processes. |
True or False: Genes are made up of sequences with three-base segments called codons. | True |
True or False: Different codons code for unique amino acids. Some amino acids may not be coded for by more than one codon. | False. Some amino acids may be coded for by more than one codon. |
How many different amino acids are there? | 20 |
True or False: The order of amino acids in a protein determines the protein’s structure and function. To make a protein the gene containing the DNA, coding for that protein must first be converted into an RNA molecule. | True |
Explain transcription. | The process of synthesizing RNA from a DNA template. The cell copies the information in a gene by making complementary messenger RNA strands |
Explain translation. | The process of building a protein based on a RNA template. Messenger RNA (mRNA) strands are used as the code to assemble amino acids in the correct order to form a protein. |
During transcription, the enzyme RNA polymerase catalyzes the copying of base codes in a gene from DNA to a complementary strand of mRNA. Where does this strand go? | It travels through the cytoplasm to structures called ribosomes. |
Ribosomes are made of another kind of RNA called ribosomal RNA (rRNA). What occurs here? | Protein synthesis. |
What does tRNA (transfer RNA) do? | tRNA, carries amino acids to the ribosomes and attaches them in the order coded on the mRNA molecule. |
How are amino acids linked together? | With peptide bonds. These then form a protein. |
When does DNA replication begin? | DNA replication begins when the enzyme helicase unwinds a segment of DNA and separates the two strands of the double helix, forming a structure called a replication fork. |
True or False: DNA polymerase can add nucleotides only to a free 3' end of a growing segment, never to a 5' end, so DNA synthesis can occur in the 5' to 3' direction only. | True. |
Which strand of the replication fork can be continuously be assembled? How does the other strand complete synthesis? | The leading strand. Synthesis of the other strand—the lagging strand—occurs in segments. |
What are the names of each DNA strand during replication? | Leading and Lagging. |
Suppose a scientist extracts DNA from one cell and inserts it into another cell. What is the scientist most likely trying to accomplish? | A genetic copy. |
What molecules are transferred by tRNA? | Amino Acids |
What determines the genetic code of a region of DNA? | The order of nitrogenous bases |
Which of the following best describes the structure of a typical molecule of DNA? | Double-stranded helix |
What does a chromosome consist of? | Tightly wound DNA and proteins |
What is the most inclusive component of an organism? | Chromosomes. |
What does adenine bind to in a molecule of DNA? | A sugar phosphate group and thymine. |
What molecule begins DNA replication? | Helicase |
Which of the following is NOT a type of RNA? Ribosomal, messenger, translational, transfer | Translational. |
Messenger RNA delivers a "message" from ________ to ________. | DNA; ribosomal RNA |
Many amino acids come together to form a ________. | Protein |
RNA contains ________. | 4 possible nitrogenous bases. |
How are the four DNA bases typically abbreviated? | A, T, C, G |