Biology Unit 5 Exam

1. The mRNA sequence ACU codes for the amino acid Thr. A mutation occurs, and the resulting mRNA sequence is AUU. What amino aci will replace Thr?

Val

Met

Ile

Ala

Codon = Amino Acid
AUU = Ile (Isoleucine)
NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

Explanation

Codon = Amino Acid
AUU = Ile (Isoleucine)
NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

2. This molecule below is an example of the monomer of a protein. What is this molecule called?

Amino acid

Carbohydrate

Fatty acid

Nucleotide

Amino acids are put together to build a protein. Nucleotides are found in nucleic acids (DNA/RNA). Fatty acids are lipids.

Explanation

Amino acids are put together to build a protein. Nucleotides are found in nucleic acids (DNA/RNA). Fatty acids are lipids.

3. Which of the following is NOT a STOP codon?

UGA

UAG

UAA

UGG

Stop = UGA, UAG, & UAA

Explanation

Stop = UGA, UAG, & UAA

4. In eukaryotes, DNA

Is located in the nucleus.

Floats freely in the cytoplasm.

Is located in the ribosomes.

Is circular.

DNA is found in the nucleus or eukaryotes and in the cytoplasm of prokaryotes.

Explanation

DNA is found in the nucleus or eukaryotes and in the cytoplasm of prokaryotes.

5. The cell cycle is the

Time from prophase until cytokinesis.

Period of time between the birth and the death of a cell.

Time it takes for one cell to undergo mitosis.

Series of events that cells go through as they grow and divide.

The cell cycle shows the changes that the cell undergoes as it grows to the point where it is ready to divide. That is NOT the same thing as cell death.
It includes Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase, & Cytokinesis

Explanation

The cell cycle shows the changes that the cell undergoes as it grows to the point where it is ready to divide. That is NOT the same thing as cell death.
It includes Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase, & Cytokinesis

6. What is the role of the spindle during mitosis?

It duplicates the DNA.

It breaks down the nuclear membrane.

It makes the chromosomes visible.

It helps separate the chromosomes.

The spindle is used to separate the sister chromatids of each chromosome during anaphase so that both cells have identical copies of the DNA.

Explanation

The spindle is used to separate the sister chromatids of each chromosome during anaphase so that both cells have identical copies of the DNA.

7. One difference between cell division in plant cells and in animal cells is that plant cells have

Centromeres.

Chromatin.

Centrioles.

A cell plate.

Cytokinesis in Plants = cell plate forms (beginning of a new cell wall)
Cytokinesis in Animals = cleavage furrow (cell membrane pinches together)

Explanation

Cytokinesis in Plants = cell plate forms (beginning of a new cell wall)
Cytokinesis in Animals = cleavage furrow (cell membrane pinches together)

8. How many codons are needed to specify one amino acid? (Hint: It is NOT asking for the number of nitrogen bases.)

1

3

6

20

1 codon = 1 amino acid

Explanation

1 codon = 1 amino acid

9. The 3 base sequence found on a mRNA molecule is called a ______.

Codon

Anticodon

Amino acid

Polypeptide

A codon is found on mRNA and codes for a single amino acid.

Explanation

A codon is found on mRNA and codes for a single amino acid.

10. The first phase of mitosis is called

Prophase.

Interphase.

Metaphase.

Anaphase.

Prophase is the first & longest stage of mitosis. This is where the nucleolus disappears, chromosomes condense, nuclear membrane disappears, and the spindle forms.

Explanation

Prophase is the first & longest stage of mitosis. This is where the nucleolus disappears, chromosomes condense, nuclear membrane disappears, and the spindle forms.

11. DNA is copied during a process called

Replication.

Translation.

Transcription.

Transformation.

DNA replication produces 2 identical molecules of DNA during S phase of interphase.

Explanation

DNA replication produces 2 identical molecules of DNA during S phase of interphase.

12. DNA contains the sugar

Ribose.

Deoxyribose.

Glucose.

Lactose.

DNA (deoxyribonucleic acid) contains the sugar deoxyribose

Explanation

DNA (deoxyribonucleic acid) contains the sugar deoxyribose

13.

Refer to the diagram above. The structures labeled B are called

Centrioles.

Sister chromatids.

Centromeres.

Spindles.

The sister chromatids are identical copies of DNA produced during DNA replication. The entire structure is called the chromosome.

Explanation

The sister chromatids are identical copies of DNA produced during DNA replication. The entire structure is called the chromosome.

14. Where does transcription occur?

Nucleus

Nucleolus

Cytoplasm

Ribosome

Transcription occurs in the nucleus because that is where the DNA is.

Explanation

Transcription occurs in the nucleus because that is where the DNA is.

15. During DNA replication, which of the following is the enzyme responsible for "unzipping" the DNA by breaking the hydrogen bonds between nucleotides?

Helicase

MRNA

RNA polymerase

DNA polymerase

Helicase breaks the hydrogen bonds between the 2 strand of DNA. DNA polymerase adds nucleotides to build the new strand of DNA. mRNA is NOT an enzyme. RNA polymerase is used during transcription to make mRNA.

Explanation

Helicase breaks the hydrogen bonds between the 2 strand of DNA. DNA polymerase adds nucleotides to build the new strand of DNA. mRNA is NOT an enzyme. RNA polymerase is used during transcription to make mRNA.

16. Which of the following happens when a cell divides?

It becomes more difficult for the cell to get enough oxygen and nutrients.

The cell has DNA overload.

The cell’s volume increases.

Each daughter cell receives its own copy of the parent cell’s DNA.

DNA overload, difficulty transporting substances, and increasing volume are reasons a cell divides.
AFTER division, you have 2 cells with identical DNA.

Explanation

DNA overload, difficulty transporting substances, and increasing volume are reasons a cell divides.
AFTER division, you have 2 cells with identical DNA.

17. Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGUUACUGAGGGCUGA Use the genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.

Lys in Person A is replaced with Glu in Person B.

Phe in Person A is replaced with Leu in Person B.

Persons A and B have identical amino acid sequences.

A stop codon is generated in Person B and not in Person A.

Person A: AUGGUUACUAAGGGCUGA
Person B:...........................GAG................
Person A: AAG = Lys (Lysine)
Person B: GAG = Glu (Glutamine)
NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

Explanation

Person A: AUGGUUACUAAGGGCUGA
Person B:...........................GAG................
Person A: AAG = Lys (Lysine)
Person B: GAG = Glu (Glutamine)
NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

18.

Refer to the diagram above. During which phase(s) of mitosis are chromosomes like the one shown visible?

Metaphase only

Anaphase and prophase

Anaphase and interphase

Prophase and metaphase

Chromosomes condense and become visible during Prophase. They line up in the middle during Metaphase. These structures are no longer visible during Anaphase because the sister chromatids are pulled apart. DNA is in the form of Chromatin at the end of Telophase and throughout Interphase.

Explanation

Chromosomes condense and become visible during Prophase. They line up in the middle during Metaphase. These structures are no longer visible during Anaphase because the sister chromatids are pulled apart. DNA is in the form of Chromatin at the end of Telophase and throughout Interphase.

19. The 3 base sequence found on a tRNA molecule is called a ______.

Codon

Anticodon

Amino acid

Polypeptide

Anticodons are on tRNA. They are used to decode the codons on mRNA.
anTicodon = Trna

Explanation

Anticodons are on tRNA. They are used to decode the codons on mRNA.
anTicodon = Trna

20. The mRNA sequence GUG-GAG-AGC codes for what amino acid sequence?

Trp-Arg-Asp

Val-Asp-Arg

Leu-Pro-Trp

Val-Glu-Ser

codon = amino acid
GUG = Val (Valine)
GAG = Glu (Glutamine)
AGC = Ser (Serine)

NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

Explanation

codon = amino acid
GUG = Val (Valine)
GAG = Glu (Glutamine)
AGC = Ser (Serine)

NOTE: this will be asking a different sequence on the test. Make sure you know HOW to use the chart.

21. Refer to the diagram above. Picture D is which phase of mitosis?

Prophase

Metaphase

Anaphase

Telophase

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

Explanation

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

22. How many codons are needed to specify three amino acids? (Hint: It is NOT asking for the number of nitrogen bases.)

1

3

6

9

3 codons = 3 amino acids

Explanation

3 codons = 3 amino acids

23. When during the cell cycle is a cell's DNA replicated?

M phase

G2 phase

S phase

G1 phase

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis; During M phase = cell division

Explanation

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis; During M phase = cell division

24. Which of the following is a correct statement about the events of the cell cycle?

The M phase is usually the longest phase.

DNA replicates during cytokinesis.

Interphase consists of the G1, S, and G2 phases.

Little happens during the G1 and G2 phases.

Most of the cell cycle consists of Interphase (G1 = growth, S = DNA replication, & G2 = preparation for mitosis.
Cell Division (M phase) is much shorter and consists of mitosis (division of the nucleus) & cytokinesis (division of the cytoplasm)

Explanation

Most of the cell cycle consists of Interphase (G1 = growth, S = DNA replication, & G2 = preparation for mitosis.
Cell Division (M phase) is much shorter and consists of mitosis (division of the nucleus) & cytokinesis (division of the cytoplasm)

25. Another name for a protein is ______.

RNA

RNA polymerase

Amino acid

Polypeptide

Polypeptides are chains of amino acids bonded together by peptide bonds. It is another name for a protein because there are multiple peptide bonds.

Explanation

Polypeptides are chains of amino acids bonded together by peptide bonds. It is another name for a protein because there are multiple peptide bonds.

26. DNA replication results in two DNA molecules,

Each with two new strands.

One with two new strands and the other with two original strands.

Each with one new strand and one original strand.

Each with two original strands.

The original strand is used as a template to build the new strand using the rules of base pairing (A=T, G=C). This produces 2 identical DNA molecules.

Explanation

The original strand is used as a template to build the new strand using the rules of base pairing (A=T, G=C). This produces 2 identical DNA molecules.

27. During DNA replication, which of the following is the enzyme responsible for adding nucleotides to form the complementary strand of DNA?

Helicase

MRNA

RNA polymerase

DNA polymerase

Helicase breaks the hydrogen bonds between the 2 strand of DNA. DNA polymerase adds nucleotides to build the new strand of DNA. mRNA is NOT an enzyme. RNA polymerase is used during transcription to make mRNA.

Explanation

Helicase breaks the hydrogen bonds between the 2 strand of DNA. DNA polymerase adds nucleotides to build the new strand of DNA. mRNA is NOT an enzyme. RNA polymerase is used during transcription to make mRNA.

28. The process by which a cell's nucleus divides so that two eukaryotic daughter cells can form is called

Interphase.

Cytokinesis.

Metaphase.

Mitosis.

Mitosis is specifically the division of the nucleus. Cytokinesis is the division of the cytoplasm. Cell division includes both mitosis and cytokinesis.

Explanation

Mitosis is specifically the division of the nucleus. Cytokinesis is the division of the cytoplasm. Cell division includes both mitosis and cytokinesis.

29. Which of the following is the enzyme responsible for copying a gene into the complementary sequence of RNA during transcription?

Helicase

MRNA

RNA polymerase

DNA polymerase

RNA polymerase is the enzyme that builds mRNA.
Helicase & DNA polymerase are involved in DNA replication.

Explanation

RNA polymerase is the enzyme that builds mRNA.
Helicase & DNA polymerase are involved in DNA replication.

30. How many nitrogen bases are needed to specify one amino acid? (Hint: It is NOT asking for the number of codons.)

1

3

4

5

3 bases = 1 codon = 1 amino acid

Explanation

3 bases = 1 codon = 1 amino acid

31. Which nucleotide is NOT found in RNA?

Adenine

Thymine

Guanine

Cytosine

RNA does not have T. It has Uracil (U) instead.

Explanation

RNA does not have T. It has Uracil (U) instead.

32.

Refer to the diagram above. The structure labeled A is called the

Sister chromatid.

Centromere.

Spindle.

Centriole.

The centromere holds the 2 sister chromatids together.

Explanation

The centromere holds the 2 sister chromatids together.

33. During which phase of mitosis do the chromosomes line up along the middle of the dividing cell?

Anaphase

Metaphase

Prophase

Telophase

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

Explanation

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

34. Which type of RNA is made during transcription and functions as a "blueprint" for protein synthesis?

MRNA

RRNA

TRNA

RNA polymerase

DNA is copied into mRNA during transcription. mRNA acts as a copy of the instructions that goes to the ribosome so the protein can be assembled.

Explanation

DNA is copied into mRNA during transcription. mRNA acts as a copy of the instructions that goes to the ribosome so the protein can be assembled.

35. Which of the following represents the phases of mitosis in their proper sequence?

Prophase, metaphase, anaphase, telophase

Interphase, prophase, metaphase, anaphase, telophase

Interphase, prophase, metaphase, telophase

Prophase, anaphase, metaphase, telophase

Mitosis = Prophase, Metaphase, Anaphase, & Telophase. Interphase is NOT part of Mitosis.

Explanation

Mitosis = Prophase, Metaphase, Anaphase, & Telophase. Interphase is NOT part of Mitosis.

36. Refer to the diagram above. Picture B is which phase of mitosis?

Prophase

Metaphase

Anaphase

Telophase

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

Explanation

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

37. Refer to the diagram above. Picture A is which phase of mitosis?

Prophase

Metaphase

Anaphase

Telophase

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

Explanation

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

38. Which pair is correct?

G2 phase, preparation for mitosis

S phase, cell division

G1 phase, DNA replication

M phase, cell growth

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis; During M phase = cell division

Explanation

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis; During M phase = cell division

39. Which event occurs during interphase?

The cell grows.

Spindle fibers begin to form.

Centromeres divide.

Centrioles appear.

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis

Explanation

During interphase: G1 = growth; S = DNA replication; G2 = preparation for mitosis

40. What contains the instructions for making proteins?

DNA sequences called genes

RNA molecules called transfer RNA

Organelles called ribosomes

DNA, tRNA, and ribosomes

DNA contains all of the instructions for making proteins. The info in DNA is copied into mRNA. tRNA just decodes the information in mRNA. The ribosomes are made of rRNA which just bonds the amino acids that are brought by the tRNA.

Explanation

DNA contains all of the instructions for making proteins. The info in DNA is copied into mRNA. tRNA just decodes the information in mRNA. The ribosomes are made of rRNA which just bonds the amino acids that are brought by the tRNA.

41. Where does translation occur?

Nucleus

Nucleolus

Cytoplasm

Ribosome

Translation happens at the ribosome. That is where the protein is assembled.

Explanation

Translation happens at the ribosome. That is where the protein is assembled.

42. Which of the following is a nucleotide found in RNA?

Ribose + phosphate group + thymine

Ribose + phosphate group + uracil

Deoxyribose + phosphate group + uracil

Deoxyribose + phosphate group + cytosine

DNA nucleotide = deoxyribose + phosphate group + C, G, A, or T
RNA nucleotide = ribose + phosphate group + C, G, A, or U

Explanation

DNA nucleotide = deoxyribose + phosphate group + C, G, A, or T
RNA nucleotide = ribose + phosphate group + C, G, A, or U

43. What combines with sugar and a phosphate group to form a nucleotide?

Amino acid

Deoxyribose

Glycerol

Nitrogenous base

Nucleotides have a sugar, a phosphate group, and a nitrogen base (G, C, A , T, or U)

Explanation

Nucleotides have a sugar, a phosphate group, and a nitrogen base (G, C, A , T, or U)

44. Refer to the diagram above. Picture C is which phase of mitosis?

Prophase

Metaphase

Anaphase

Telophase

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

Explanation

Prophase = nucleolus disappears, chromatin condenses into chromosomes, nuclear membrane dissolves, & spindle forms
Metaphase = chromosomes attach to the spindle and are pulled into the middle of the cell
Anaphase = sister chromatids are pulled apart and move to opposite ends of the cell
Telophase = sister chromatids unwind into chromatin, spindle breaks down, nuclear membrane reforms, & nucleolus reappears
Cytokinesis = division of the cytoplasm; occurs during telophase

45. What happens during the process of translation?

Messenger RNA is made from DNA.

The cell uses information from messenger RNA to produce proteins.

Transfer RNA is made from messenger RNA.

Copies of DNA molecules are made.

Translation is the process of building a protein. mRNA is the copy of the instructions. tRNA decodes mRNA & transfers the amino acids. rRNA bonds the amino acids together.

Explanation

Translation is the process of building a protein. mRNA is the copy of the instructions. tRNA decodes mRNA & transfers the amino acids. rRNA bonds the amino acids together.