anaphy chapter 3 Flashcards
What is the cell theory, and why is it fundamental to understanding biology?
The cell theory states that all living organisms are composed of one or more cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. This theory is fundamental because it establishes that the cell is the basic structural and functional unit of all living organisms.
What distinguishes eukaryotic cells from prokaryotic cells?
Eukaryotic cells have a true nucleus enclosed by a membrane and contain membrane-bound organelles, whereas prokaryotic cells lack a nucleus and membrane-bound organelles.
Describe the fluid mosaic model of the plasma membrane.
The fluid mosaic model describes the plasma membrane as a dynamic structure where lipids and proteins can move laterally within the layer. The membrane is composed of a bilayer of phospholipids with embedded proteins, which allows the membrane to be flexible while maintaining its structural integrity.
What roles do phospholipids, proteins, and carbohydrates play in the plasma membrane?
Phospholipids form the basic structure of the membrane, creating a hydrophobic barrier. Proteins serve various functions, including transport, signal reception, and structural support. Carbohydrates, often attached to proteins or lipids, are involved in cell recognition and communication.
Explain the difference between passive and active transport.
Passive transport does not require energy and occurs when molecules move from an area of higher concentration to one of lower concentration (e.g., diffusion, osmosis). Active transport requires energy, typically in the form of ATP, to move molecules against their concentration gradient (e.g., sodium-potassium pump).
What is osmosis, and how does it affect cells in hypotonic, hypertonic, and isotonic environments?
Osmosis is the diffusion of water across a semipermeable membrane. In a hypotonic environment, water enters the cell, causing it to swell. In a hypertonic environment, water leaves the cell, causing it to shrink. In an isotonic environment, there is no net water movement, and the cell remains the same size.
Describe the sodium-potassium pump and its significance.
The sodium-potassium pump is an active transport mechanism that moves three sodium ions out of the cell and two potassium ions into the cell against their concentration gradients. This pump is crucial for maintaining the cell’s electrochemical gradient, which is essential for processes like nerve impulse transmission.
What is the cytoplasm, and what are its primary components?
The cytoplasm is the material within a cell, excluding the nucleus. It consists of cytosol, a gel-like substance, and the organelles, which perform specific functions necessary for cellular life.
Compare the rough and smooth endoplasmic reticulum in terms of structure and function.
The rough endoplasmic reticulum (RER) is studded with ribosomes and is involved in protein synthesis and processing. The smooth endoplasmic reticulum (SER) lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
What is the function of lysosomes in a cell?
Lysosomes contain digestive enzymes that break down waste materials, cellular debris, and foreign invaders like bacteria, playing a key role in cellular waste disposal and recycling.
What is the primary function of mitochondria in cells?
Mitochondria are the powerhouse of the cell, responsible for producing ATP through cellular respiration, which provides energy for cellular processes.
Describe the structure of a mitochondrion.
Mitochondria have a double membrane structure, with an outer membrane and a highly folded inner membrane (cristae) that increases surface area for ATP production. The inner space, called the matrix, contains enzymes, DNA, and ribosomes.
How does the electron transport chain contribute to ATP production?
The electron transport chain, located in the inner mitochondrial membrane, uses high-energy electrons from NADH and FADH2 to pump protons across the membrane, creating a gradient. The flow of protons back through ATP synthase drives the production of ATP.
What are the main functions of the nucleus in a eukaryotic cell?
The nucleus houses the cell’s genetic material (DNA) and is responsible for regulating gene expression, storing hereditary information, and coordinating cell activities like growth, metabolism, and reproduction.
How is DNA organized within the nucleus?
DNA is organized into chromatin, which is composed of DNA wrapped around histone proteins. During cell division, chromatin condenses to form chromosomes.
What is the difference between transcription and translation?
Transcription is the process of copying a gene’s DNA sequence into messenger RNA (mRNA), which occurs in the nucleus. Translation is the process where the mRNA is decoded by ribosomes to synthesize proteins, occurring in the cytoplasm.
What are the main stages of the cell cycle?
The cell cycle consists of interphase (G1, S, and G2 phases) where the cell grows and DNA is replicated, and the mitotic phase (mitosis and cytokinesis) where the cell divides.
How does mitosis differ from meiosis?
Mitosis is a process of cell division that results in two genetically identical daughter cells, used for growth and repair. Meiosis is a special type of cell division that produces four genetically unique gametes, used for sexual reproduction.
What is the role of checkpoints in the cell cycle?
Checkpoints in the cell cycle ensure that each stage is completed accurately, preventing errors such as DNA damage from being passed on to daughter cells. They can halt the cycle to allow for repairs or trigger apoptosis if the damage is irreparable.
What roles do mRNA, tRNA, and rRNA play in protein synthesis?
mRNA carries the genetic code from DNA to the ribosome, tRNA brings the correct amino acids to the ribosome, and rRNA forms the core of the ribosome’s structure and catalyzes peptide bond formation.
Describe the process of translation.
During translation, the ribosome reads the mRNA codons, and tRNA molecules bring the corresponding amino acids, which are linked together to form a polypeptide chain, eventually folding into a functional protein.
What are the different types of cell signaling mechanisms?
Autocrine signaling occurs when a cell targets itself, paracrine signaling targets nearby cells, and endocrine signaling involves hormones that travel through the bloodstream to distant cells.
How do receptor proteins facilitate cellular communication?
Receptor proteins on the cell surface or inside the cell bind to signaling molecules (ligands) and trigger a response in the cell, such as activating a signaling pathway or gene expression.
What is apoptosis, and why is it important?
Apoptosis is programmed cell death, a process that eliminates damaged or unnecessary cells without causing harm to the surrounding tissue, crucial for development and maintaining cellular health.
How does cellular aging affect cell function?
Cellular aging leads to a decline in cellular function, reduced ability to divide, and increased susceptibility to damage. This process contributes to the aging of tissues and organisms.
What is the Hayflick limit, and how does it relate to aging?
The Hayflick limit refers to the number of times a normal human cell can divide before it stops due to telomere shortening. This limit is associated with the aging process as cells lose the ability to proliferate.
Which of the following statements is NOT part of the cell theory?
A) All living organisms are composed of one or more cells.
B) The cell is the most basic unit of life.
C) All cells have a nucleus.
D) All cells arise from pre-existing cells
C) All cells have a nucleus.
Which of the following is true about prokaryotic cells?
A) They have a well-defined nucleus.
B) They lack membrane-bound organelles.
C) They are generally larger than eukaryotic cells.
D) They have a complex cytoskeleton.
B) They lack membrane-bound organelles
The plasma membrane’s primary function is to:
A) Generate energy for the cell.
B) Control what enters and exits the cell.
C) Store genetic information.
D) Produce proteins.
B) Control what enters and exits the cell.
Which component of the plasma membrane is primarily responsible for its fluid nature?
A) Carbohydrates
B) Cholesterol
C) Integral proteins
D) Phospholipids
D) Phospholipids
The fluid mosaic model describes the plasma membrane as:
A) A rigid, static structure.
B) A double layer of protein molecules.
C) A flexible layer made of phospholipids with proteins embedded within it.
D) A single layer of carbohydrates and proteins.
C) A flexible layer made of phospholipids with proteins embedded within it
Which of the following is a function of membrane proteins?
A) Act as enzymes to speed up chemical reactions.
B) Serve as recognition sites for cell-cell communication.
C) Transport molecules across the membrane.
D) All of the above.
D) All of the above.
Passive transport differs from active transport because:
A) Passive transport requires energy, while active transport does not.
B) Active transport moves substances down their concentration gradient.
C) Passive transport moves substances down their concentration gradient without energy.
D) Active transport involves osmosis, while passive transport involves diffusion.
C) Passive transport moves substances down their concentration gradient without energy.
In osmosis, water moves:
A) From a hypertonic solution to a hypotonic solution.
B) From a hypotonic solution to a hypertonic solution.
C) Equally in both directions across the membrane.
D) Against the concentration gradient.
B) From a hypotonic solution to a hypertonic solution
The sodium-potassium pump:
A) Moves sodium ions into the cell and potassium ions out of the cell.
B) Requires ATP to function.
C) Is an example of facilitated diffusion.
D) Moves sodium and potassium ions in equal numbers.
B) Requires ATP to function.
The rough endoplasmic reticulum (RER) is associated with:
A) Lipid synthesis.
B) Protein synthesis.
C) Carbohydrate metabolism.
D) Energy production.
B) Protein synthesis
the cytoplasm is composed of:
A) Cytosol, organelles, and inclusions.
B) DNA and RNA.
C) Proteins and lipids only.
D) Just organelles.
A) Cytosol, organelles, and inclusions.
Which organelle contains digestive enzymes that break down waste materials and cellular debris?
A) Lysosome
B) Mitochondrion
C) Ribosome
D) Golgi apparatus
A) Lysosome
The Golgi apparatus is responsible for:
A) Energy production.
B) Protein modification and sorting.
C) DNA replication.
D) Cellular respiration.
B) Protein modification and sorting.
The primary function of mitochondria is:
A) Protein synthesis.
B) ATP production.
C) Lipid storage.
D) Photosynthesis
B) ATP production.
Which of the following best describes the inner membrane of the mitochondrion?
A) It is smooth and featureless.
B) It contains cristae to increase surface area.
C) It is involved in protein synthesis.
D) It functions in DNA replication
B) It contains cristae to increase surface area
The electron transport chain, involved in ATP production, is located in the:
A) Cytosol
B) Inner mitochondrial membrane
C) Plasma membrane
D) Nucleus
B) Inner mitochondrial membrane
The nucleus of a cell contains:
A) Cytoplasm.
B) Genetic material (DNA).
C) Ribosomes.
D) Mitochondria
B) Genetic material (DNA)
Chromatin is:
A) A type of protein found in the cytoplasm.
B) DNA wrapped around histone proteins.
C) RNA that is being translated into protein.
D) The liquid portion of the cytoplasm
B) DNA wrapped around histone proteins.
Transcription is the process of:
A) Converting DNA into RNA.
B) Synthesizing proteins from amino acids.
C) Replicating DNA before cell division.
D) Modifying proteins in the Golgi apparatus.
A) Converting DNA into RNA.
During which phase of the cell cycle does DNA replication occur?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
B) S phase
Which of the following best describes mitosis?
A) It reduces the chromosome number by half.
B) It results in two genetically identical daughter cells.
C) It occurs in germ cells only.
D) It includes the division of the cytoplasm.
B) It results in two genetically identical daughter cells
Cytokinesis in animal cells differs from plant cells in that:
A) Animal cells form a cell plate, while plant cells do not.
B) Animal cells divide the cytoplasm using a cleavage furrow.
C) Plant cells undergo binary fission instead of cytokinesis.
D) Animal cells do not use a spindle apparatus during division.
B) Animal cells divide the cytoplasm using a cleavage furrow.
A critical checkpoint that ensures DNA is undamaged and fully replicated occurs at the:
A) G1/S checkpoint
B) S/G2 checkpoint
C) G2/M checkpoint
D) Metaphase checkpoint
C) G2/M checkpoint
mRNA is responsible for:
A) Carrying genetic information from DNA to the ribosome.
B) Transferring amino acids to the ribosome during protein synthesis.
C) Forming the structure of the ribosome.
D) Modifying proteins after translation
A) Carrying genetic information from DNA to the ribosome.
Translation occurs in the:
A) Nucleus
B) Cytoplasm at the ribosome
C) Golgi apparatus
D) Mitochondria
B) Cytoplasm at the ribosome
A codon is a sequence of three nucleotides that:
A) Signals the start of DNA replication.
B) Specifies a particular amino acid during protein synthesis.
C) Marks the end of a gene.
D) Is involved in the folding of proteins.
B) Specifies a particular
Which of the following structures is found inside the nucleus?
A) Mitochondria
B) Ribosomes
C) Chromatin
D) Golgi apparatus
C) Chromatin
The nuclear envelope is composed of how many membranes?
A) One
B) Two
C) Three
D) Four
Answer: B) Two
The nucleolus is primarily involved in the production of:
A) DNA
B) Ribosomal RNA (rRNA)
C) mRNA
D) tRNA
Answer: B) Ribosomal RNA (rRNA)
Which of the following is NOT a function of the nucleus?
A) Storing genetic information
B) Regulating gene expression
C) Synthesizing proteins
D) Directing cell division
Answer: C) Synthesizing proteins
What is the function of nuclear pores?
A) To store DNA
B) To regulate the passage of molecules between the nucleus and cytoplasm
C) To synthesize ribosomes
D) To protect the DNA
B) To regulate the passage of molecules between the nucleus and cytoplasm
The nuclear matrix is:
A) A network of fibers within the nucleus providing structural support
B) A layer of enzymes that repairs DNA
C) The site of ribosome assembly
D) The liquid component of the nucleus
A) A network of fibers within the nucleus providing structural support
Which of the following describes euchromatin?
A) Tightly packed DNA, transcriptionally inactive
B) Loosely packed DNA, transcriptionally active
C) DNA that is found only in the nucleolus
D) DNA that has been permanently silenced
B) Loosely packed DNA, transcriptionally active
What is the role of histones in the nucleus?
A) They replicate DNA
B) They help package DNA into chromatin
C) They produce RNA
D) They are involved in protein synthesis
B) They help package DNA into chromatin
Which of the following occurs in the nucleoplasm?
A) Protein synthesis
B) DNA replication and RNA transcription
C) Glycolysis
D) Lipid metabolism
B) DNA replication and RNA transcription
The nuclear lamina is composed of:
A) Microtubules
B) Intermediate filaments
C) Actin filaments
D) Centrioles
Answer: B) Intermediate filaments
What happens during the S phase of the cell cycle in the nucleus?
A) Cell growth
B) DNA replication
C) Mitosis
D) Cytokinesis
B) DNA replication
Structure of Chromosomes
Chromosomes are most easily visible during which phase of cell division?
A) Interphase
B) Prophase
C) Metaphase
D) Telophase
Answer: C) Metaphase
The region of a chromosome that is attached to spindle fibers during cell division is the:
A) Telomere
B) Centromere
C) Chromatid
D) Chromatin
Answer: B) Centromere
Which of the following statements about sister chromatids is correct?
A) They are identical copies of a chromosome connected by a centromere.
B) They are different versions of a gene.
C) They are found only in prokaryotic cells.
D) They are found in the nucleolus.
A) They are identical copies of a chromosome connected by a centromere.
The chromosomal structure that links a pair of sister chromatids is called the:
A) Chromosome arm
B) Telomere
C) Centromere
D) Histone
Answer: C) Centromere
Which enzyme is responsible for adding repetitive nucleotide sequences to the ends of chromosomes?
A) DNA polymerase
B) Helicase
C) Telomerase
D) Ligase
C) Telomerase
Telomeres are important because they:
A) Protect the ends of chromosomes from deterioration.
B) Code for essential proteins.
C) Assist in the separation of chromatids.
D) Prevent the formation of centromeres.
A) Protect the ends of chromosomes from deterioration.
Chromatin is composed of:
A) RNA and proteins
B) DNA and proteins
C) Lipids and carbohydrates
D) Proteins and lipids
B) DNA and proteins
What is the function of histones in chromosome structure?
A) To replicate DNA
B) To help organize DNA into nucleosomes
C) To separate sister chromatids
D) To transport DNA out of the nucleus
B) To help organize DNA into nucleosomes
Which of the following is true about heterochromatin?
A) It is loosely packed and transcriptionally active.
B) It is tightly packed and transcriptionally inactive.
C) It is found only in the nucleolus.
D) It is identical to euchromatin.
B) It is tightly packed and transcriptionally inactive.
Ribosomes are primarily composed of:
A) DNA and proteins
B) RNA and proteins
C) Lipids and carbohydrates
D) RNA and lipids
B) RNA and proteins
What is the primary difference between homologous chromosomes?
A) They are genetically identical.
B) They carry different versions of the same genes.
C) One is always larger than the other.
D) They only occur in prokaryotic cells.
B) They carry different versions of the same genes.
During which phase of meiosis do homologous chromosomes separate?
A) Prophase I
B) Metaphase I
C) Anaphase I
D) Telophase I
C) Anaphase I
Where are ribosomes commonly found in the cell?
A) In the nucleus
B) Attached to the rough endoplasmic reticulum and free in the cytoplasm
C) In the Golgi apparatus
D) In the mitochondria
B) Attached to the rough endoplasmic reticulum and free in the cytoplasm
Which of the following is the primary function of ribosomes?
A) DNA replication
B) Protein synthesis
C) Lipid metabolism
D) ATP production
B) Protein synthesis
Ribosomes that are attached to the endoplasmic reticulum are involved in the synthesis of:
A) Cytoplasmic proteins
B) Membrane-bound proteins and secretory proteins
C) Mitochondrial proteins
D) Lysosomal enzymes
Answer: B) Membrane-bound proteins and secretory proteins
The site of protein synthesis within the ribosome is called the:
A) A-site
B) P-site
C) E-site
D) S-site
B) P-site
What is the primary function of the rough endoplasmic reticulum (RER)?
A) Lipid synthesis
B) Protein synthesis
C) DNA replication
D) ATP production
B) Protein synthesis
Ribosomal subunits are assembled in the:
A) Nucleus
B) Nucleolus
C) Cytoplasm
D) Endoplasmic reticulum
B) Nucleolus
Which of the following best describes the function of free ribosomes?
A) They synthesize proteins that will be secreted out of the cell.
B) They synthesize proteins that remain in the cytosol.
C) They attach to the rough endoplasmic reticulum.
D) They are involved in lipid synthesis.
B) They synthesize proteins that remain in the cytosol.
Which structure is characteristic of the rough endoplasmic reticulum (RER)?
A) Ribosomes attached to its surface
B) A smooth, ribosome-free surface
C) Vesicles attached to its surface
D) Enzymes for detoxification
A) Ribosomes attached to its surface
The smooth endoplasmic reticulum (SER) is primarily involved in:
A) Protein synthesis
B) Lipid metabolism and detoxification
C) Glycolysis
D) DNA replication
B) Lipid metabolism and detoxification
Which of the following functions is NOT associated with the smooth endoplasmic reticulum (SER)?
A) Synthesis of steroid hormones
B) Detoxification of drugs and poisons
C) Protein synthesis
D) Storage of calcium ions
C) Protein synthesis
Which of the following cell types is likely to have an abundance of smooth endoplasmic reticulum (SER)?
A) Neurons
B) Muscle cells
C) Liver cells
D) Skin cells
C) Liver cells
In which of the following ways does the rough endoplasmic reticulum (RER) differ from the smooth endoplasmic reticulum (SER)?
A) The RER is involved in lipid synthesis, while the SER is involved in protein synthesis.
B) The RER has ribosomes attached to it, while the SER does not.
C) The RER detoxifies drugs, while the SER produces ATP.
D) The RER synthesizes carbohydrates, while the SER synthesizes lipids.
Answer: B) The RER has ribosomes attached to it, while the SER does not.
Golgi Apparatus
The primary function of the Golgi apparatus is:
A) Synthesis of proteins
B) Modification, sorting, and packaging of proteins and lipids
C) DNA replication
D) ATP production
B) Modification, sorting, and packaging of proteins and lipids
Which of the following best describes the structure of the Golgi apparatus?
A) A series of flattened membrane-bound sacs
B) A single, large, spherical structure
C) A network of tubules and vesicles
D) A double membrane structure with ribosomes
A) A series of flattened membrane-bound sacs
Which of the following statements is true about the Golgi apparatus?
A) It is involved in the synthesis of ribosomes.
B) It receives proteins from the rough ER for further modification.
C) It is the primary site of ATP production in the cell.
D) It stores and replicates DNA.
B) It receives proteins from the rough ER for further modification.
The Golgi apparatus is most abundant in cells that are specialized for:
A) Energy production
B) Protein secretion
C) Phagocytosis
D) Glycolysis
B) Protein secretion
Proteins and lipids leave the Golgi apparatus in structures called:
A) Lysosomes
B) Vesicles
C) Ribosomes
D) Peroxisomes
B) Vesicles
What happens to proteins as they pass through the Golgi apparatus?
A) They are degraded into amino acids.
B) They are synthesized from amino acids.
C) They are modified, packaged, and sorted for transport.
D) They are used to produce energy.
C) They are modified, packaged, and sorted for transport.
Which organelle is primarily responsible for forming secretory vesicles?
A) Nucleus
B) Golgi apparatus
C) Mitochondria
D) Rough ER
Answer: B) Golgi apparatus
Which of the following is a common content of secretory vesicles?
A) DNA
B) Ribosomes
C) Hormones and enzymes
D) Lysosomal enzymes
C) Hormones and enzymes
What happens to secretory vesicles when they reach the plasma membrane?
A) They are absorbed into the cytoplasm.
B) They fuse with the plasma membrane and release their contents outside the cell.
C) They are transported to the nucleus.
D) They disintegrate and release enzymes into the cell.
B) They fuse with the plasma membrane and release their contents outside the cell.
Secretory vesicles are involved in:
A) Transporting substances out of the cell via exocytosis
B) Storing genetic material
C) Breaking down cellular waste
D) Generating energy in the form of ATP
A) Transporting substances out of the cell via exocytosis
Lysosomes are primarily involved in:
A) Protein synthesis
B) Breaking down waste materials and cellular debris
C) DNA replication
D) Lipid synthesis
B) Breaking down waste materials and cellular debris
Secretory vesicles are important for which cellular process?
A) Apoptosis
B) Protein synthesis
C) Cell signaling
D) DNA replication
C) Cell signaling
What is the main function of peroxisomes?
A) Digestion of cellular waste
B) Detoxification of harmful substances and breakdown of fatty acids
C) Synthesis of proteins
D) Replication of DNA
B) Detoxification of harmful substances and breakdown of fatty acids
Which enzyme is commonly found in peroxisomes and is responsible for breaking down hydrogen peroxide?
A) DNA polymerase
B) Catalase
C) Amylase
D) Pepsin
B) Catalase
Lysosomes contain enzymes that are most effective in:
A) Alkaline environments
B) Acidic environments
C) Neutral environments
D) Hypotonic environments
B) Acidic environments
Which of the following cell types is likely to have a high number of lysosomes?
A) Muscle cells
B) Red blood cells
C) Phagocytic white blood cells
D) Neurons
C) Phagocytic white blood cells
The process by which lysosomes degrade worn-out organelles is called:
A) Exocytosis
B) Endocytosis
C) Autophagy
D) Pinocytosis
C) Autophagy
What happens to peroxisomes when they accumulate too much hydrogen peroxide?
A) They release the hydrogen peroxide into the cytoplasm.
B) They convert hydrogen peroxide into water and oxygen using catalase.
C) They transport hydrogen peroxide to the mitochondria.
D) They store hydrogen peroxide until it is needed.
B) They convert hydrogen peroxide into water and oxygen using catalase.
the primary function of mitochondria is:
A) DNA replication
B) Protein synthesis
C) ATP production through cellular respiration
D) Lipid metabolism
C) ATP production through cellular respiration
Which of the following structures is unique to mitochondria and is crucial for its function?
A) Cristae
B) Thylakoids
C) Lysosomes
D) Nucleolus
A) Cristae
Mitochondria are often referred to as the “powerhouses” of the cell because they:
A) Produce most of the cell’s ATP
B) Synthesize all the cell’s proteins
C) Store the cell’s genetic material
D) Detoxify harmful substances
A) Produce most of the cell’s
The cytoskeleton is composed of which of the following types of fibers?
A) Microfilaments, microtubules, and intermediate filaments
B) Actin, myosin, and tropomyosin
C) Collagen, elastin, and reticular fibers
D) Keratin, myosin, and dynein
A) Microfilaments, microtubules, and intermediate filaments
Which cytoskeletal element is primarily responsible for cell movement and muscle contraction?
A) Microtubules
B) Microfilaments
C) Intermediate filaments
D) Centrioles
B) Microfilaments
Microtubules are involved in all of the following processes EXCEPT:
A) Cell division (mitosis)
B) Vesicle transport
C) Maintaining cell shape
D) DNA replication
D) DNA replication
Which motor protein interacts with microtubules to facilitate intracellular transport?
A) Myosin
B) Kinesin
C) Actin
D) Collagen
B) Kinesin
Intermediate filaments primarily function to:
A) Provide tensile strength to cells
B) Facilitate cellular motility
C) Assist in DNA replication
D) Generate ATP
A) Provide tensile strength to cells
Which of the following is a protein component of microfilaments?
A) Tubulin
B) Actin
C) Keratin
D) Lamin
B) Actin
Cilia and flagella are composed of:
A) Microfilaments
B) Intermediate filaments
C) Microtubules
D) Actin filaments
C) Microtubules
Translation
Translation is the process of synthesizing:
A) DNA from RNA
B) RNA from DNA
C) Proteins from mRNA
D) Lipids from fatty acids
C) Proteins from mRNA
In which cellular organelle does translation occur?
A) Nucleus
B) Ribosome
C) Golgi apparatus
D) Endoplasmic reticulum
B) Ribosome
The start codon for translation is:
A) UGA
B) UAA
C) AUG
D) UAG
C) AUG
Which of the following best describes the role of the ribosome during translation?
A) It catalyzes the formation of peptide bonds between amino acids.
B) It transcribes DNA into mRNA.
C) It edits and processes mRNA.
D) It degrades misfolded proteins.
A) It catalyzes the formation of peptide bonds between amino acids.
Which type of RNA carries the genetic code from the nucleus to the ribosome?
A) tRNA
B) mRNA
C) rRNA
D) miRNA
B) mRNA
tRNA molecules are responsible for:
A) Carrying amino acids to the ribosome
B) Synthesizing mRNA
C) Transporting mRNA out of the nucleus
D) Catalyzing peptide bond formation
A) Carrying amino acids to the ribosome
What occurs at the A-site of the ribosome during translation?
A) tRNA enters and binds to the mRNA codon.
B) Peptide bonds are formed between amino acids.
C) The completed polypeptide chain is released.
D) mRNA is transcribed into protein.
A) tRNA enters and binds to the mRNA codon.
The termination of translation occurs when the ribosome encounters:
A) A start codon
B) A stop codon
C) An anticodon
D) An exon
B) A stop codon
Which of the following is true about the G1 phase of the cell cycle?
A) It is the phase where DNA replication occurs.
B) It is the phase where the cell grows and carries out normal functions.
C) It is the phase where the cell divides into two daughter cells.
D) It is the phase where the nuclear envelope dissolves.
B) It is the phase where the cell grows and carries out normal functions.
During which phase of mitosis do the chromosomes align at the cell’s equatorial plane?
A) Prophase
B) Metaphase
C) Anaphase
D) Telophase
B) Metaphase
Cytokinesis occurs during which part of the cell cycle?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
D) M phase
Which phase of the cell cycle is characterized by the replication of DNA?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
B) S phase
The G2 phase of the cell cycle is primarily concerned with:
A) DNA synthesis
B) Cell growth and preparation for mitosis
C) Separation of sister chromatids
D) Nuclear envelope reformation
B) Cell growth and preparation for mitosis
Cell differentiation is the process by which:
A) Cells replicate their DNA
B) Unspecialized cells become specialized in structure and function
C) Cells die in a controlled manner
D) Cells grow and divide
B) Unspecialized cells become specialized in structure and function
Which checkpoint ensures that all chromosomes are properly aligned before the cell proceeds with division?
A) G1 checkpoint
B) G2 checkpoint
C) Metaphase checkpoint
D) S phase checkpoint
C) Metaphase checkpoint
What is the role of cyclins and cyclin-dependent kinases (CDKs) in the cell cycle?
A) They signal the start of DNA replication.
B) They regulate the progression of the cell cycle.
C) They degrade damaged DNA.
D) They form the mitotic spindle.
B) They regulate the progression of the cell cycle.
Which of the following best describes a stem cell?
A) A cell that has reached its final specialized form
B) A cell that can differentiate into various cell types
C) A cell that only undergoes apoptosis
D) A cell that cannot divide
B) A cell that can differentiate into various cell types
Which of the following factors can influence cell differentiation?
A) Gene expression
B) Environmental signals
C) Cell-to-cell interactions
D) All of the above
D) All of the above
During development, the differentiation of cells into specific tissues is guided by:
A) Random mutations
B) Master regulatory genes
C) Apoptosis
D) DNA replication
B) Master regulatory genes
Which of the following is an example of a differentiated cell?
A) Zygote
B) Neuron
C) Stem cell
D) Blastocyst
B) Neuron
What is the term for the process by which a stem cell becomes a blood cell?
A) Neurogenesis
B) Hematopoiesis
C) Myogenesis
D) Apoptosis
B) Hematopoiesis
Gene expression refers to the process by which:
A) DNA is replicated
B) The information in a gene is used to produce a functional product, such as a protein
C) Cells undergo apoptosis
D) Chromosomes are separated during mitosis
B) The information in a gene is used to produce a functional product, such as a protein
Which of the following is the first step in gene expression?
A) Translation
B) Replication
C) Transcription
D) Mitosis
C) Transcription
Which of the following is a common method of regulating gene expression in eukaryotic cells?
A) RNA interference
B) DNA methylation
C) Histone modification
D) All of the above
D) All of the above
Transcription factors are proteins that:
A) Degrade mRNA after translation
B) Help initiate and regulate the process of transcription
C) Transport amino acids to the ribosome
D) Splice introns from pre-mRNA
B) Help initiate and regulate the process of transcription
Alternative splicing allows for:
A) The production of different proteins from a single gene
B) The repair of damaged DNA
C) The replication of DNA
D) The degradation of RNA
A) The production of different proteins from a single gene
The process of translating mRNA into protein is directly regulated by:
A) Promoter regions
B) Transcription factors
C) Ribosomes
D) DNA polymerase
C) Ribosomes
What role does mRNA play in gene expression?
A) It carries the genetic code from DNA to the ribosome.
B) It catalyzes the formation of peptide bonds.
C) It degrades faulty proteins.
D) It unwinds the DNA helix during replication.
A) It carries the genetic code from DNA to the ribosome.
Apoptosis is best described as:
A) Uncontrolled cell division
B) Programmed cell death
C) A process of cell differentiation
D) The process of DNA replication
B) Programmed cell death
Which of the following is a key feature of apoptosis?
A) Inflammation and swelling of the surrounding tissue
B) Fragmentation of the DNA and cellular components
C) Uncontrolled cell growth and tumor formation
D) Random, accidental cell death
B) Fragmentation of the DNA and cellular components
Apoptosis is critical for:
A) Eliminating damaged or harmful cells
B) Promoting the growth of cancer cells
C) Increasing cell proliferation
D) Protecting cells from oxidative stress
A) Eliminating damaged or harmful cells
Which of the following proteins is directly involved in the regulation of apoptosis?
A) p53
B) Tubulin
C) Actin
D) RNA polymerase
A) p53
Caspases are enzymes that:
A) Replicate DNA
B) Degrade cellular components during apoptosis
C) Assist in mRNA splicing
D) Facilitate cell differentiation
B) Degrade cellular components during apoptosis
What is the outcome of apoptosis for the organism?
A) Tissue damage and inflammation
B) Replacement of lost cells
C) Removal of cells that are no longer needed or are potentially harmful
D) Uncontrolled cell proliferation
C) Removal of cells that are no longer needed or are potentially harmful
