Ap Bio -- Quizlet -- ULTIMATE Mcq

A mutation replaces thymine with another base in DNA. Which base pairing would be directly affected?

Adenine-Thymine

A polypeptide is best described as:

A chain of amino acids forming part or all of a protein

A regulatory sequence in DNA is important because it:

Controls the timing and level of gene expression

After glycolysis, which molecule enters the mitochondria to be further processed for energy production during aerobic respiration?

Pyruvate

Chaperone proteins assist in which major cellular task?

Proper folding of new or misfolded proteins

During bacterial translation, what special codon signals where to begin adding amino acids to a new protein?

Start codon (AUG)

During intense exercise, which metabolic pathway supplies quick energy by converting glucose to pyruvate?

Glycolysis

During mRNA processing, what typically happens to introns?

They are spliced out and removed

During transcription, what is the role of the template strand of DNA?

It serves as the pattern for RNA synthesis

Heat shock proteins (HSPs) are most likely to be upregulated in response to which cellular condition?

Elevated temperatures or cellular stress

How can DNA methylation serve as a clinical biomarker?

By identifying silenced tumor suppressor genes in cancer

How can a conformational change in a protein affect its function?

It can activate or inactivate the protein's activity

How do hydrophobic molecules behave in the cell?

They cluster together away from water

How do microRNAs (miRNAs) typically regulate gene expression?

By binding to mRNA and blocking translation or causing degradation

How do molecular interactions affect enzyme activity?

They help enzymes recognize and bind specific substrates

How does carbon dioxide influence acid-base balance in the body?

It combines with water to form carbonic acid, affecting pH

How does the presence of oxygen in the atmosphere primarily impact ecological processes on Earth?

By facilitating aerobic respiration in living organisms

How does the proteasome participate biochemically in targeting misfolded proteins?

It breaks them down into small peptides after being marked by ubiquitin

If a segment of DNA has a high amount of guanine, which base will also be abundant in that segment?

Cytosine

In bacterial gene expression, what is the function of mRNA?

Serving as a template for protein synthesis

In cell signaling, why is phosphorylation of proteins important?

It adds phosphate groups to proteins, changing their activity

In double-stranded DNA, the molecule cytosine pairs consistently with:

Guanine

In eukaryotic microorganisms, why are mitochondria essential?

They provide the majority of ATP through cellular respiration

In the DNA double helix, adenine pairs specifically with which base?

Thymine

In the context of cell chemistry, what role do acids play?

They donate hydrogen ions to solutions

Ionic bonds commonly form between which?

Positive and negative ions transferring electrons

Protein misfolding is problematic for cells because:

Misfolded proteins can become toxic and disrupt normal cellular functions

The leading strand in DNA replication is synthesized:

Continuously in the 5’ to 3’ direction

Transcription factors are proteins that:

Bind to specific DNA sequences to regulate gene expression

What defines an organic molecule in cells?

Presence of carbon and usually hydrogen atoms

What describes a typical role of a disaccharide in nutrition?

As a quick energy source in foods like table sugar

What does it mean that DNA strands are antiparallel?

The two strands run in opposite directions

What happens to chromatin structure after histone acetylation in skin cells?

Chromatin relaxes, increasing gene transcription

What is a codon in the context of bacterial gene expression?

A three-nucleotide sequence on mRNA that codes for an amino acid

What is a key role of hydrogen bonds in living cells?

They stabilize the structure of DNA and proteins

What is a likely cellular result of increased histone acetylation?

Enhanced gene transcription due to relaxed chromatin

What is the common outcome for proteins tagged with ubiquitin through ubiquitination?

They are directed to the proteasome for degradation

What is the end result of protein synthesis in living cells?

Production of polypeptide chains

What is the general term for molecules like chlorophyll that absorb specific wavelengths of light?

Pigment

What is the key function of the Electron Transport Chain (ETC)?

Generating the most ATP from the breakdown of nutrients

What is the main benefit of alternative splicing in gene expression?

Allows a single gene to produce multiple proteins

What is the main function of the bacterial ribosome?

Translating mRNA into protein

What is the main function of the replication fork during prokaryotic DNA replication?

It separates DNA strands, allowing each to serve as a template for synthesis

What is the main role of a silencer in transcriptional control?

Inhibits gene expression when bound by regulatory proteins

What is the main role of amino acids in living organisms?

Building blocks for proteins

What is the main role of chromatin remodeling complexes in the nucleus?

Move nucleosomes to regulate gene accessibility

What is the main role of nucleic acids in a cell?

Storing and transmitting genetic information

What is the name of the process that incorporates atmospheric CO2 into organic molecules during photosynthesis?

Carbon Fixation

What is the practical importance of the Genetic Code?

It specifies how nucleotide sequences are translated into amino acids

What is the primary function of protein kinases in post-translational modifications?

Add phosphate groups to proteins

What is the primary function of splicing in eukaryotic cells?

Removing introns from pre-mRNA

What is the primary role of a primer during DNA replication?

To initiate DNA synthesis by providing a starting point for DNA polymerase

What is the process by which the movement of protons across a membrane generates ATP?

Chemiosmosis

What is the role of DNA ligase in DNA replication?

Joining Okazaki fragments on the lagging strand

What is the role of NADPH in the Calvin Cycle?

Providing electrons and hydrogen for sugar synthesis

What is the role of a stop codon in bacterial protein synthesis?

Signaling the end of translation

What is the role of proteolytic cleavage in protein maturation?

Removes signal sequences or activates proteins by cutting peptide bonds

What is the significance of the double helix structure of DNA in cellular processes?

It enables the storage and accurate replication of genetic information

What is the term for a particle of light that initiates the light-dependent reactions in photosynthesis?

Photon

What is true about covalent bonds in biological molecules?

Electrons are shared between atoms

What occurs during transcription in bacteria?

RNA is made from a DNA template

What role do exons play in eukaryotic genes?

They encode the regions of protein-coding genes present in the final mature mRNA

What type of process occurs in the absence of oxygen and can result in the formation of lactic acid or ethanol?

Anaerobic

What would happen if helicase did not function during DNA replication?

The DNA double helix would not unwind

When DNA is replicated, what is produced as the complementary strand?

A strand with bases paired specifically to the template strand

Where does DNA replication start on a bacterial chromosome?

Origin of Replication (oriC)

Where in the chloroplast does the Calvin Cycle take place?

Stroma

Where is an ester linkage commonly found in the body?

Connecting fatty acids to glycerol in triglycerides

Where is the anticodon located, and what is its function?

On the tRNA to match mRNA codons during translation

Which best describes the impact of limited water supply on organisms in an ecosystem?

Restriction of survival and reproduction

Which best describes the risk associated with protein aggregation in cells?

Impaired cellular functions and potential development of disease

Which best describes the role of rRNA in the cell?

Forming the core of ribosomes and catalyzing protein assembly

Which cellular process primarily depends on the ubiquitin-proteasome system?

Degrading unwanted or misfolded proteins

Which compound is produced in muscle cells during intense exercise when oxygen is scarce?

Lactic Acid

Which cycle is responsible for carbon fixation and sugar production in the stroma of chloroplasts?

Calvin Cycle

Which cycle occurs in the mitochondrial matrix and generates high-energy electron carriers from acetyl-CoA?

Citric Acid Cycle

Which describes a hydrophilic molecule in a cell?

It dissolves well in water

Which describes the main benefit of an operon in prokaryotic cells?

Allows for simultaneous regulation of multiple genes involved in the same process

Which enzyme begins the synthesis of RNA from a DNA template in bacteria?

RNA polymerase

Which enzyme catalyzes the fixation of carbon dioxide in the first step of the Calvin Cycle?

Rubisco

Which enzyme is responsible for adding nucleotides to a growing DNA strand during bacterial chromosome replication?

DNA Polymerase

Which enzyme is responsible for removing phosphate groups from phosphorylated proteins in the cell?

Phosphatase

Which enzyme synthesizes short RNA sequences to serve as primers during DNA replication?

Primase

Which enzyme uses the flow of protons across the mitochondrial membrane to synthesize ATP from ADP and phosphate?

ATP Synthase

Which example shows a polymer in action within a cell?

A chain of amino acids forming a protein

Which function best describes tRNA in bacterial translation?

It carries amino acids to the ribosome

Which is an example of an inorganic molecule found in cells?

Water (H₂O)

Which molecule carries high-energy electrons from glycolysis and the citric acid cycle to the electron transport chain?

NADH

Which molecule donates electrons to the electron transport chain at a later point than NADH, resulting in less ATP production per molecule?

FADH₂

Which molecule is formed from pyruvate before entering the citric acid cycle during cellular respiration?

Acetyl-CoA

Which molecule is the primary fuel broken down during cellular respiration to provide energy for cells?

Glucose

Which of the following best describes an epigenetic modification?

A chemical change that affects gene expression without altering DNA sequence

Which of the following best describes the function of an enhancer in gene regulation?

Increases the rate of transcription when bound by specific proteins

Which of the following best describes the primary function of DNA in living cells?

It stores and transmits genetic information

Which of the following best describes the role of ubiquitin in protein turnover within cells?

It tags damaged or misfolded proteins for degradation

Which of the following illustrates the role of fatty acids in biological membranes?

Forming the hydrophobic tails of phospholipids

Which of the following is a key function of proteins in cells?

Serving as a structural component

Which of the following is a primary function of RNA polymerase II in eukaryotic cells?

Synthesizing messenger RNA (mRNA) during transcription

Which of the following is a primary function of carbohydrates in living cells?

Providing immediate energy for cellular processes

Which of the following scenarios involves the formation of a peptide bond?

Two amino acids joining during protein synthesis