ITS ALL ABOUT DNA & RNA
What are the four nucleotides that make up DNA?
Adenine, guanine, cytosine, thymine
__________________ bind to exposed strands to prevent H-bonds from reforming
Single stranded binding proteins
Negatively DNA is wrapped around special positively charged proteins called _____________
histones
What enzyme is responsible for reading a DNA template and synthesizing RNA?
Each gene is unique and codes for synthesis of a single polypeptide is known as what hypothesis?
One gene-one polypeptide hypothesis
What nitrogenous base is present in RNA, but not in DNA?
URACIL
Which enzyme fills in gaps in the lagging strand between Okazaki fragments and removes RNA primers to replace them with DNA nucleotides?
DNA polymerase I
What is cell senescence?
Cells lose ability to function properly as a person ages. Occurs as individuals age
What is a codon and how many are there?
A codon is a group of three base pairs that code for an individual amino acid
There are 64 codons - 61 sense codons that specify amino acids. Most amino acids specified by several codons (redundancy) Ex: CCU, CCC, CCA, CCG all specify proline
There are three stop codons that end a polypeptide encoding mRNA sequence
Which scientist(s) claimed that DNA was the hereditary molecule in 1952?
Hershey and Chase
Showed that bacteriophage DNA (not protein) enters bacterial cells to direct the life cycle of the virus
What are the three components of a nucleotide?
sugar, phosphate, nitrogenous base
What is the name of the smaller fragments of DNA produced by DNA polymerase on the lagging strand of DNA during replication?
Okazaki fragments
What is a telomere and where is it located?
To prevent the loss of essential coding regions of DNA, zones of repetitive, non-coding sequences are found at the ends of eukaryotic chromosomes
These sequences are called telomeres
Every time DNA replicates, part of its telomeres are lost, but the coding regions of DNA remain
After transcription the process of splicing will remove noncoding segments of RNA called what?
INTRONS
The nitrogenous base content of a sample of DNA was found to be 32% adenine. Determine the amounts of thymine in this sample.
32%
DNA uses a ______________ sugar, whereas RNA uses a _______________ sugar
deoxyribose, ribose
The enzyme ____________ creates RNA primers to start replication and _________________ removes and replaces them with DNA.
Why do we need to package our DNA? Describe 2 reasons.
1) Fit inside chromosomes – inside nucleus.
2) So it doesn’t get damaged
How would you transcribe the following DNA sequence into RNA? AATAGCCAT
UUAUCGGUA
Which scientists are credited with discovering the structure of DNA? Explain their findings.
Watson and Crick - discovered that a DNA molecule consists of two polynucleotide chains twisted around each other into a right-handed double helix
Franklin - found that DNA was a double helix and rotated in a clockwise direction
DNA is semi-conservative. What does this mean?
Separating the two parent strands and building a new, complementary replacement strand for each
Newly-synthesized DNA molecules has one old strand and one new strand
Which of the following is false about the leading strand?
a) uses 3' - 5' template strand as a guide
b) is built continuously towards replication fork
c) has multiple RNA primer
c) is incorrect. The leading strand has one single primer
What would happen if we didn't have telomeres?
If chromosomes were not capped by telomeres, a small portion of a gene near the end of a chromosome could be lost every time DNA replication occurred
What are the three post transcriptional modifications made to mRNA after it is translated but before it is transported out of the nucleus?
mRNA SPLICING, POLY A TAIL, 5' GUANINE CAP
____________ DNA is HUGE and linear, therefore it has multiple origins of replication
EUKARYOTIC