Cells, Viruses, and Molecular Biology: Complete Practice Question Bank

What is a prokaryotic cell?

A prokaryotic cell is a type of cell that lacks a nucleus and membrane-bound organelles, typically smaller and simpler than eukaryotic cells.

What is a eukaryotic cell?

A eukaryotic cell is a type of cell that has a nucleus and membrane-bound organelles, generally larger and more complex than prokaryotic cells.

What structures do eukaryotic cells contain that prokaryotic cells do not?

Eukaryotic cells contain structures such as a nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes, which are not found in prokaryotic cells.

Do prokaryotic cells have a nucleus? If not, where is their DNA found?

No, prokaryotic cells do not have a nucleus; their DNA is found in a region called the nucleoid.

Do prokaryotic cells contain membrane-bound organelles? Explain.

No, prokaryotic cells do not contain membrane-bound organelles; they have simpler structures that carry out functions without being enclosed by membranes.

Which type of cell is generally smaller and simpler: prokaryotic or eukaryotic?

Prokaryotic cells are generally smaller and simpler than eukaryotic cells.

Which type of cell appeared earlier in evolutionary history?

Prokaryotic cells appeared earlier in evolutionary history than eukaryotic cells.

What types of organisms have prokaryotic cells?

Prokaryotic cells are found in organisms such as bacteria and archaea.

What types of organisms have eukaryotic cells?

Eukaryotic cells are found in organisms such as plants, animals, fungi, and protists.

List structures that are found in BOTH prokaryotic and eukaryotic cells.

Both prokaryotic and eukaryotic cells contain ribosomes, cytoplasm, and a cell membrane.

Compare the location and organization of DNA in prokaryotic and eukaryotic cells.

In prokaryotic cells, DNA is circular and located in the nucleoid region, while in eukaryotic cells, DNA is linear and organized into chromosomes within the nucleus.

Compare the size and complexity of prokaryotic and eukaryotic cells.

Prokaryotic cells are generally smaller (0.1 to 5.0 micrometers) and simpler, while eukaryotic cells are larger (10 to 100 micrometers) and more complex.

What is the function of the nucleus?

The nucleus stores the cell's genetic information and coordinates activities such as growth, metabolism, and reproduction.

What is the function of chromosomes?

Chromosomes carry genetic information in the form of genes and ensure accurate replication and distribution during cell division.

What is the function of mitochondria?

Mitochondria are the powerhouses of the cell, responsible for producing ATP through cellular respiration.

What is the function of chloroplasts?

Chloroplasts are responsible for photosynthesis, converting light energy into chemical energy in the form of glucose.

What is the function of the Golgi apparatus?

The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

What is the function of rough endoplasmic reticulum?

Rough endoplasmic reticulum is involved in the synthesis and processing of proteins, with ribosomes attached to its surface.

What is the function of smooth endoplasmic reticulum?

Smooth endoplasmic reticulum is involved in lipid synthesis, detoxification, and calcium ion storage.

What is the function of vesicles?

Vesicles transport materials within the cell and can also help in the secretion of substances outside the cell.

What is the function of a vacuole?

Vacuoles store nutrients, waste products, and help maintain turgor pressure in plant cells.

What is the function of the cell wall?

The cell wall provides structural support and protection to plant cells, fungi, and some prokaryotes.

What is the function of the cell membrane?

The cell membrane regulates the movement of substances in and out of the cell and provides protection and support.

What is the function of ribosomes?

Ribosomes are the sites of protein synthesis, translating messenger RNA into polypeptide chains.

Which organelle is the main site of protein synthesis?

Ribosomes are the main site of protein synthesis in the cell.

Which organelle modifies, sorts, and packages proteins?

The Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery.

Which organelle contains the cell's genetic information?

The nucleus contains the cell's genetic information.

Which organelle is associated with cellular respiration and ATP production?

Mitochondria are associated with cellular respiration and ATP production.

Which organelle carries out photosynthesis?

Chloroplasts carry out photosynthesis.

Which organelles/structures would you expect in a plant cell but not an animal cell?

Plant cells typically contain chloroplasts, a large central vacuole, and a cell wall, which are not found in animal cells.

What does DNA stand for?

DNA stands for deoxyribonucleic acid.

What is the main function of DNA?

The main function of DNA is to store and transmit genetic information that guides the development and functioning of living organisms.

What is a nucleotide?

A nucleotide is the basic building block of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

What are the three parts of a DNA nucleotide?

The three parts of a DNA nucleotide are a deoxyribose sugar, a phosphate group, and a nitrogenous base.

What sugar is found in DNA?

The sugar found in DNA is deoxyribose.

What is the role of the phosphate group in a nucleotide?

The phosphate group links nucleotides together to form the DNA backbone and provides structural stability.

What are the four nitrogenous bases in DNA?

The four nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).

What forms the sugar-phosphate backbone of DNA?

The sugar-phosphate backbone of DNA is formed by alternating sugar and phosphate groups linked by covalent bonds.

What forms the 'rungs' of the DNA ladder?

The 'rungs' of the DNA ladder are formed by pairs of nitrogenous bases bonded together through hydrogen bonds.

What does it mean to say DNA is a double helix?

DNA is described as a double helix because it consists of two strands twisted around each other, resembling a spiral staircase.

What does anti-parallel mean when describing the two DNA strands?

Anti-parallel means that the two strands of DNA run in opposite directions, with one strand oriented 5' to 3' and the other 3' to 5'.

State the DNA complementary base-pairing rule.

The complementary base-pairing rule states that adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G).

Which bases are purines and which are pyrimidines?

In DNA, adenine and guanine are purines, while cytosine and thymine are pyrimidines.

How many hydrogen bonds normally form between adenine and thymine?

Two hydrogen bonds normally form between adenine and thymine.

How many hydrogen bonds normally form between cytosine and guanine?

Three hydrogen bonds normally form between cytosine and guanine.

Why is complementary base pairing important to DNA structure and replication?

Complementary base pairing ensures accurate replication of DNA and maintains the integrity of the genetic code.

How are nucleotides linked together to form a DNA strand?

Nucleotides are linked together by covalent bonds between the phosphate group of one nucleotide and the sugar of the next.

How is a DNA molecule different from a single nucleotide?

A DNA molecule is a long chain of nucleotides that forms a double helix, while a single nucleotide is just one building block of DNA.

What is the relationship between DNA, genes, chromosomes, and proteins?

DNA contains genes, which are segments that code for proteins; genes are organized into chromosomes, which are structures that ensure proper segregation during cell division.

Explain why the order of nitrogenous bases matters.

The order of nitrogenous bases determines the genetic code, which dictates the synthesis of proteins and ultimately influences an organism's traits.

What is DNA replication?

DNA replication is the process by which a cell makes an identical copy of its DNA before cell division.

Why must DNA replicate?

DNA must replicate to ensure that each daughter cell receives an exact copy of the genetic material during cell division.

When in a cell's life does DNA replication occur?

DNA replication occurs during the S phase of the cell cycle, before mitosis or meiosis.

Give one situation in which cells would need to replicate DNA.

Cells need to replicate DNA during growth, tissue repair, or reproduction to produce new cells.

Where does DNA replication occur in a eukaryotic cell?

DNA replication occurs in the nucleus of a eukaryotic cell.

What happens to the double helix at the start of replication?

At the start of replication, the double helix unwinds and separates into two strands, allowing each strand to serve as a template for new DNA synthesis.

What enzyme separates or 'unzips' the two DNA strands?

The enzyme helicase separates the two DNA strands.

What happens to the hydrogen bonds between complementary bases during replication?

The hydrogen bonds break, allowing the strands to separate.

What does each original DNA strand act as during replication?

Each original DNA strand serves as a template for the synthesis of a new complementary strand.

How do free nucleotides know where to attach?

Free nucleotides pair with their complementary bases on the template strand according to base-pairing rules.

What enzyme adds complementary DNA nucleotides to the growing strand?

DNA polymerase adds complementary DNA nucleotides to the growing strand.

What is produced at the end of DNA replication?

Two identical daughter DNA molecules are produced.

Compare the two daughter DNA molecules to the original DNA molecule.

Each daughter DNA molecule consists of one original strand and one newly synthesized strand.

Why is DNA replication described as semi-conservative?

Because each new DNA molecule contains one original strand and one new strand.

How many old strands and new strands are found in each replicated DNA molecule?

Each replicated DNA molecule contains one old strand and one new strand.

Explain the role of complementary base pairing in making replication accurate.

Complementary base pairing ensures that the correct nucleotides are added, maintaining the fidelity of the DNA sequence.

Outline DNA replication in the correct order from unwinding to two DNA molecules.

1. Unwinding of the double helix; 2. Separation of strands; 3. Base pairing of free nucleotides; 4. Formation of new strands; 5. Resulting in two identical DNA molecules.

If a DNA template strand is ACG TTA GGC, what new strand will be produced?

The new strand produced will be TGC AAC CCG.

What does RNA stand for?

RNA stands for ribonucleic acid.

Compare the sugar in DNA with the sugar in RNA.

DNA contains deoxyribose sugar, while RNA contains ribose sugar.

Compare the number of strands in DNA with RNA.

DNA is double-stranded, while RNA is typically single-stranded.

Compare the nitrogenous bases in DNA and RNA.

DNA contains adenine, thymine, cytosine, and guanine; RNA contains adenine, uracil, cytosine, and guanine.

Which RNA base replaces thymine?

Uracil replaces thymine in RNA.

Compare the usual locations of DNA and RNA in a eukaryotic cell.

DNA is primarily located in the nucleus, while RNA is found in the nucleus and cytoplasm.

Compare the main functions of DNA and RNA.

DNA stores genetic information, while RNA is involved in protein synthesis.

List at least three similarities between DNA and RNA.

1. Both are nucleic acids; 2. Both are made of nucleotides; 3. Both play roles in genetic information.

List at least three differences between DNA and RNA.

1. DNA is double-stranded, RNA is single-stranded; 2. DNA contains thymine, RNA contains uracil; 3. DNA has deoxyribose, RNA has ribose.

Why is RNA useful as an intermediate between DNA and protein production?

RNA serves as a messenger that carries genetic information from DNA to the ribosomes for protein synthesis.

What is protein synthesis?

Protein synthesis is the process by which cells create proteins based on the information encoded in DNA.

Why do cells need to make proteins?

Cells need to make proteins for various functions, including structure, enzymes, and signaling.

Give one example of when protein synthesis might occur.

Protein synthesis occurs during cell growth and repair.

What are the two major stages of protein synthesis?

The two major stages are transcription and translation.

Write the information pathway often summarized as DNA -> RNA -> protein.

The pathway is DNA transcribed into RNA, which is then translated into protein.

What are amino acids, and how are they related to proteins?

Amino acids are the building blocks of proteins, linked together in specific sequences to form polypeptides.

What is a polypeptide?

A polypeptide is a chain of amino acids linked by peptide bonds, which folds into a functional protein.

What is transcription?

Transcription is the process of synthesizing RNA from a DNA template.

Where does transcription occur in a eukaryotic cell?

Transcription occurs in the nucleus of a eukaryotic cell.

What molecule is used as the template during transcription?

The DNA molecule serves as the template during transcription.

What molecule is produced during transcription?

Messenger RNA (mRNA) is produced during transcription.

State the base-pairing rules when DNA is transcribed into mRNA.

Adenine pairs with uracil, and cytosine pairs with guanine.

Why is uracil used instead of thymine in RNA?

Uracil is used in RNA because it is structurally simpler than thymine and is sufficient for RNA's functions.

What happens to the DNA double helix during transcription?

The DNA double helix unwinds and separates to allow RNA synthesis.

What enzyme builds the RNA strand during transcription?

RNA polymerase builds the RNA strand during transcription.

What happens to the mRNA after transcription?

The mRNA undergoes processing, including capping and polyadenylation, before being transported to the cytoplasm.

Given DNA template TAC GGA CTT, write the mRNA sequence.

The mRNA sequence will be AUG CCU GAA.

Given DNA template ACG TTT CCA, write the mRNA sequence.

The mRNA sequence will be UGC AAA GGU.

What is translation?

Translation is the process of synthesizing proteins from mRNA at the ribosome.

Where does translation occur?

Translation occurs in the cytoplasm at the ribosome.

What cell structure carries out translation?

Ribosomes carry out translation.

What is a codon?

A codon is a sequence of three RNA bases that specifies a particular amino acid.