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Biology

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1.) Which of the following statements describes purines and pyrimidines in DNA molecules?

a. purines from hydrogen bonds with purines

b. pyrimidines consist of a one-ring structure

c. pyrimidines form hydrogen bonds with purines.

d. pyrimidines form covalent bonds with purines.

e. Adenine and guanine are pyrimidines

2.) Arrange the steps of DNA replication in the order that they occur.

RNA primers are removed

DNA ligase joins DNA fragments together.

Helicase unwinds the DNA double helix

RNA primers are added

Single-stranded DNA-binding proteins bind to each template strand

DNA polymerase synthesizes DNA.

3.) Identify the key structural features of a DNA molecule.

a. DNA bases are always paired purine with pyrimidine

b. strong ionic bonds and hydrophobic interaction hold DNA together.

c. DNA contains the nucleotide bases adenine, thymine, guanine, cytosine, and uracil.

d. DNA is most often found as a left-handed helix, commonly referred to as A-DNA.

e. DNA strands are antiparallel and include a 5' end and a 3' end.

f. The backbone of DNA is made of a sugar and a phosphate molecule.

4.) The diagram depicts DNA that is undergoing replication. Lable the components of the replication process.

5.) The following diagram depicts the general structure of DNA, and a single nucleotide is circled. Label the diagram with the names of the three components of a nucleotide.

6.) Choose the DNA nucleotide bases that complement guanine and adenine.

guanine- a. guanine. b. cytosine. c. thymine. or d. adenine.

adenine- a. guanine. b. cytosine. c. thymine. or d. adenine.

7.) Classify each mutation example as definitely positive, definitely negative, or most likely netural. Each category has two examples

8.) Identify the statements that describe the structure of DNA.

a. The five-carbon sugar of DNA is called ribose.

b. A DNA double helix contains two sugar-phosphate backbones oriented in opposite directions.

c. Adenine is paired with thymine, and guanine is paired with cytosine.

d. The five-carbon sugar of DNA is called deoxyribose.

e. Adenine is paired with cytosine, and guanine is paired with thymine.

9.) Which enzyme separates the two complimentary strands of DNA during DNA replication?

a. ligase

b. primase

c. DNA polymerase

d. helicase

10.) an altercation in the nucleotide sequence of a gene can alter the gene product. Each sentence below is made up of three-letter words, representing mRNA codons.

THE FAT CAT SAT

THE CAR WAS RED

THE DOG RAN

The same sentences are written below with a substitution, deletion, or insertion, much as a gene may have a substitution, deletion, or insertion mutation. Identify which sentence represents a substitution, which represents a deletion, and which represents an insertion.