DNA Structure & Replication Guide

DNA Structure and Replication Worksheet deoxyribose sugar, phosphate, nitrogen base What are the parts of a nucleotide? deoxyribose What kind of sugar is found in a nucleotide? nitrogenous base Which nucleotide component contains nitrogen? adenine, thymine, guanine, cytosine What are the 4 nitrogen bases of DNA? nitrogenous base What part(s) of the nucleotides make up the rungs of the "ladder"? antiparallel In DNA, are the rungs parallel or antiparallel? thymine When one nucleotide contains adenine, what type of base is the adenine attached to on the opposite nucleotide strand? two The two strands of DNA are held together with hydrogen bonds between the nitrogen bases, these are weak bonds between polar molecules; how many hydrogen bonds connect adenine and thymine? guanine When one nucleotide contains cytosine, what type of base if the cytosine attached to on the opposite nucleotide strand? three How many hydrogen bonds connect cytosine and guanine? adenine and thymine are attracted to each other and will have equal components Write a rule for how adenine and thymine are arranged in the ladder of DNA guanine and cytosine are attracted to each other and will have equal components Write a rule for how cytosine and guanine are arranged in the ladder of DNA 3'-TAGGTC-5' What are the complimentary bases on the strand 5'-ATCCAG-3' it is held together by hydrogen bonds and they twist to make a helix Describe the double helix shape of DNA hydrogen bonds between nucleotides break What is the 1st step in DNA replication? strand of DNA separate What is the 2nd step in DNA replication? free nucleotides are attracted to exposed bases on the loose strands of DNA What is the 3rd step in DNA replication? hydrogen bonds between nucleotides form What is the 4th step in DNA replication? enzyme What type of biological molecule is DNA helicase? breaks hydrogen bonds between the nitrogen bases What s the role of DNA helicase in the replication of DNA? Chargraff's rule What rule is used to join free nucleotides to the exposed bases of the DNA? it has 1 parent strand and 1 daughter strand Why is DNA replication called semi-conservative? the parent has the correct coding and can repair the daughter strand because of the complimentary base polymerase 1, enzymes can spot errors and can figure out the correct base pair from the parent strand DNA molecules can be tens of thousands of base pairs in length. Mistakes in DNA replication lead to mutations, which may or may not be harmful to an organism. How does semi-conservative replication help prevent mutations during DNA replication? 31% Percentage of each type of base: adenine in humans 28% Percentage of each type of base: adenine in cows 29% Percentage of each type of base: adenine in salmon 27% Percentage of each type of base: adenine in wheat 31% Percentage of each type of base: adenine in yeast 19% Percentage of each type of base: guanine in humans 22% Percentage of each type of base: guanine in cows 21% Percentage of each type of base: guanine in salmon 23% Percentage of each type of base: guanine in wheat 19% Percentage of each type of base: guanine in yeast 19% Percentage of each type of base: cytosine in humans 1/2 22% Percentage of each type of base: cytosine in cows 21% Percentage of each type of base: cytosine in salmon 23% Percentage of each type of base: cytosine in wheat 19% Percentage of each type of base: cytosine in yeast 31% Percentage of each type of base: thymine in humans 28% Percentage of each type of base: thymine in cows 29% Percentage of each type of base: thymine in salmon 27% Percentage of each type of base: thymine in wheat 31% Percentage of each type of base: thymine in yeast 2/2