Molecular biology

<p>It contains the genetic information of the cell. (A)</p> Signup and view all the answers

<p>Breakdown of cellular waste (A)</p> Signup and view all the answers

<p>Modification and packaging of proteins (D)</p> Signup and view all the answers

<p>Vacuole (A)</p> Signup and view all the answers

<p>The ER is the site of protein synthesis and lipid synthesis. (C)</p> Signup and view all the answers

<p>Anabolism builds complex molecules from simpler ones, requiring energy, while catabolism breaks down complex molecules into simpler ones, releasing energy. (D)</p> Signup and view all the answers

<p>Mitochondria and chloroplasts share a similar structural organization with eukaryotic nuclei. (D)</p> Signup and view all the answers

<p>The functional group determines the phospholipid's solubility in water, influencing its interaction with the cell membrane. (A)</p> Signup and view all the answers

<p>Pyruvic acid (C)</p> Signup and view all the answers

<p>ATP is not directly involved in either anabolic or catabolic reactions, but rather facilitates the transport of energy within the cell. (D)</p> Signup and view all the answers

<p>Aerobic respiration requires oxygen, while anaerobic respiration does not. (A)</p> Signup and view all the answers

<p>Eukaryotic cells evolved from prokaryotic cells, incorporating organelles like mitochondria and chloroplasts through endosymbiosis. (C)</p> Signup and view all the answers

<p>Amino acids (A)</p> Signup and view all the answers

<p>Phosphorylation adds a phosphate group to a protein, causing it to switch from its inactive to active state. (A)</p> Signup and view all the answers

<p>To duplicate the DNA content of the parent cell before dividing, thereby ensuring each daughter cell receives a complete copy of the genome. (A)</p> Signup and view all the answers

<p>Diploid cells contain two sets of chromosomes while haploid cells contain only one set of chromosomes. (A)</p> Signup and view all the answers

<p>GTP binding to a protein activates the protein, switching it on. (B)</p> Signup and view all the answers

<p>The cell cycle is a highly ordered and regulated process, with specific events occurring at each phase. (B)</p> Signup and view all the answers

<p>Production of gametes (eggs and sperm). (A)</p> Signup and view all the answers

<p>To ensure that each daughter cell receives a complete and identical copy of the genome. (B)</p> Signup and view all the answers

<p>Telophase. (B)</p> Signup and view all the answers

<p>The formation of chiasmata between non-sister chromatids. (A)</p> Signup and view all the answers

<p>The condensation of chromatin into chromosomes. (D)</p> Signup and view all the answers

<p>It holds homologous chromosomes together, allowing for crossing-over to occur. (A)</p> Signup and view all the answers

<p>It increases the genetic diversity of the offspring by shuffling genetic information. (D)</p> Signup and view all the answers

<p>Cohesins hold sister chromatids together, preventing their premature separation. (A)</p> Signup and view all the answers

<p>During meiosis I, homologous chromosomes pair up and exchange genetic information through crossing-over. (B)</p> Signup and view all the answers

<p>Zygotene (D)</p> Signup and view all the answers

<p>The chiasmata move towards the ends of the chromosomes. (C)</p> Signup and view all the answers

<p>Nucleus (B)</p> Signup and view all the answers

<p>Proteins - Catalyzing biochemical reactions (C)</p> Signup and view all the answers

<p>Sodium Chloride (NaCl) (A)</p> Signup and view all the answers

<p>Mitochondria (B)</p> Signup and view all the answers

<p>Animal cell (B)</p> Signup and view all the answers

<p>Only eukaryotic cells have a membrane-bound nucleus. (C)</p> Signup and view all the answers

<p>Found only in living organisms (A)</p> Signup and view all the answers

<p>Catalyzing biochemical reactions (D)</p> Signup and view all the answers

<p>To regulate the activity of cyclin-dependent kinases (B)</p> Signup and view all the answers

<p>INK4 inhibitors specifically bind to and inhibit Cdk4 and Cdk6, while CIP/KIP inhibitors affect a broader range of Cdks. (C)</p> Signup and view all the answers

<p>p27 inhibits the entry of the cell into the G0 phase by inactivating E-Cdk2 and A-Cdk2 complexes. (D)</p> Signup and view all the answers

<p>The p53 protein promotes the production of p27. (B)</p> Signup and view all the answers

<p>Apoptosis typically affects individual cells, while necrosis affects entire groups of cells. (C)</p> Signup and view all the answers

<p>Apoptosis eliminates damaged, infected, or mutated cells, preventing uncontrolled growth. (A)</p> Signup and view all the answers

<p>If DNA damage is detected, the cell cycle is arrested to allow time for repair, and apoptosis is triggered if the damage is too severe. (C)</p> Signup and view all the answers

<p>To regulate p27 production and control the cell cycle in response to DNA damage. (A)</p> Signup and view all the answers

<p>Target cells express specific receptors that bind to and receive signals from only specific signaling molecules. (A)</p> Signup and view all the answers

<p>The same signaling molecule can bind to different receptors on different target cells, leading to different intracellular pathways and responses. (D)</p> Signup and view all the answers

<p>G protein functions as a molecular switch, activating downstream signaling pathways by exchanging GDP for GTP. (D)</p> Signup and view all the answers

<p>Neurotransmitters act locally at synapses, while neurohormones act systemically through the bloodstream. (B)</p> Signup and view all the answers

<p>Adenylyl cyclase is activated by a different type of 7TM receptor compared to other pathways. (C)</p> Signup and view all the answers

<p>The cell would be unable to communicate effectively with other cells. (B)</p> Signup and view all the answers

<p>Phosphorylation can alter the protein's conformation, affecting its activity or interactions with other molecules. (D)</p> Signup and view all the answers

<p>Second messengers amplify the signal by activating multiple downstream targets, leading to a cascade effect. (C)</p> Signup and view all the answers

<p>Paracrine (D)</p> Signup and view all the answers

<p>Endocrine communication is slower and more widespread than neuronal communication. (C)</p> Signup and view all the answers

<p>Direct activation of target genes by the receptor. (C)</p> Signup and view all the answers

<p>The initial response to the signaling molecule initiates a cascade, leading to numerous downstream effects within the target cell. (B)</p> Signup and view all the answers

<p>The α subunit binds to and activates specific target proteins, triggering downstream events. (D)</p> Signup and view all the answers

<p>Protein kinases catalyze the addition of phosphate groups to target proteins, altering their function. (B)</p> Signup and view all the answers

<p>Gap junctions allow for the direct transfer of signaling molecules between adjacent cells via specialized protein channels. (C)</p> Signup and view all the answers

<p>Cyclic adenosine monophosphate (cAMP) (D)</p> Signup and view all the answers

<p>Lysosomal proteolysis is non-selective and degrades a broad range of proteins, while proteasomal proteolysis is selective and targets specific proteins marked for degradation. (B)</p> Signup and view all the answers

<p>The presence of misfolded or damaged proteins that are no longer functional. (C)</p> Signup and view all the answers

<p>The attachment of a ubiquitin molecule to the target protein. (C)</p> Signup and view all the answers

<p>They are responsible for selective degradation of specific proteins. (A)</p> Signup and view all the answers

<p>Protein degradation is essential for cellular health, but excessive degradation can lead to cellular dysfunction. (B)</p> Signup and view all the answers

<p>An influx of foreign substances, such as bacteria, into the cell. (B)</p> Signup and view all the answers

<p>Protein degradation is vital for maintaining cellular function by removing old, damaged, or excessive proteins. (B)</p> Signup and view all the answers

<p>Lysosomal proteolysis degrades both exogenous and old endogenous proteins, while proteasomal proteolysis primarily targets newly synthesized proteins. (A)</p> Signup and view all the answers

<p>The α subunit directly activates phospholipase C by binding to its catalytic domain. (A)</p> Signup and view all the answers

<p>PKC is activated by the combined action of Ca²⁺ ions and diacylglycerol (DAG), which bind to PKC and induce a conformational change. (D)</p> Signup and view all the answers

<p>PKA activates proteins involved in the breakdown of glycogen, releasing glucose for energy production. (A)</p> Signup and view all the answers

<p>Enzyme-linked receptors typically produce slower, longer-lasting responses, while 7TM receptors elicit faster, transient responses. (C)</p> Signup and view all the answers

<p>Growth factors bind to the receptor and induce dimerization, which brings together two tyrosine kinase domains, leading to autophosphorylation and activation. (D)</p> Signup and view all the answers

<p>cAMP is a second messenger that activates protein kinase A (PKA) and triggers a variety of cellular responses. (A)</p> Signup and view all the answers

<p>IP3 directly binds to and activates calcium channels on the endoplasmic reticulum (ER) membrane. (C)</p> Signup and view all the answers

<p>Activation of phospholipase C results in an increase in both IP3 and DAG levels due to the hydrolysis of phosphatidylinositol. (B)</p> Signup and view all the answers

<p>They act as specific ligands that bind to receptors on the cell membrane, initiating signaling pathways that lead to cell division. (C)</p> Signup and view all the answers

<p>G protein-coupled receptor (GPCR) pathway (D)</p> Signup and view all the answers

<p>To regulate transitions between the different phases of the cell cycle by controlling the activity of key proteins. (C)</p> Signup and view all the answers

<p>Checkpoints are critical control points that assess internal and external conditions to determine if the cell should proceed to the next phase. (A)</p> Signup and view all the answers

<p>Activating the spindle assembly checkpoint, ensuring proper chromosome alignment before mitosis begins. (C)</p> Signup and view all the answers

<p>Mitogens bind to receptors on the cell membrane, initiating a signaling cascade that ultimately leads to cell division. (B)</p> Signup and view all the answers

<p>The G1 checkpoint determines whether the cell is in a favorable environment and has sufficient nutrients to progress into the S phase. (D)</p> Signup and view all the answers

<p>The S phase follows the G1 phase, where the cell grows and replicates its DNA. (A)</p> Signup and view all the answers

<p>Carbon has a unique ability to form strong covalent bonds with other carbon atoms, allowing for the creation of diverse and complex structures. (A)</p> Signup and view all the answers

<p>Water's strong dipole moment allows it to act as a solvent for many polar molecules, facilitating chemical reactions. (D)</p> Signup and view all the answers

<p>The oxygen atom has a higher electronegativity than hydrogen atoms, creating a partial negative charge on oxygen and partial positive charges on hydrogen atoms. (D)</p> Signup and view all the answers

<p>Carbon's ability to form double and triple bonds with other carbon atoms as well as other elements. (A)</p> Signup and view all the answers

<p>Water is a solvent, transport medium, reactant in chemical reactions, and a product in other reactions, playing a multifaceted role in cellular function. (A)</p> Signup and view all the answers

<p>Both A and B contribute to fatty acid breakdown in peroxisomes. (D)</p> Signup and view all the answers

<p>Peroxisomes can be formed both de novo and by division of pre-existing peroxisomes. (D)</p> Signup and view all the answers

<p>Autolysosomes are involved in autophagy, while heterolysosomes break down external material. (B)</p> Signup and view all the answers

<p>Its function varies by species and tissue type, but it is not directly involved in any particular process. (A)</p> Signup and view all the answers

<p>The centrosome duplicates before cell division, ensuring each daughter cell receives a centrosome. (C)</p> Signup and view all the answers

<p>They break down hydrogen peroxide, preventing its accumulation and potential toxicity. (B)</p> Signup and view all the answers

<p>They produce plasmalogens, essential components of the myelin sheath. (D)</p> Signup and view all the answers

<p>The centrosome serves as a platform for the assembly of microtubules which form the fibers of the mitotic spindle. (B)</p> Signup and view all the answers

<p>The Ras-GEF complex acts as a scaffold, bringing Ras and GTP together, promoting GTP binding. (B)</p> Signup and view all the answers

<p>Kinase kinases directly phosphorylate and activate MAP kinase. (D)</p> Signup and view all the answers

<p>The active state of Ras is located on the cell membrane, while the inactive state is in the cytoplasm. (D)</p> Signup and view all the answers

<p>Binding of a GTPase activating protein (GAP) to the receptor. (D)</p> Signup and view all the answers

<p>IGF binds to a receptor tyrosine kinase, triggering a signaling cascade that ultimately leads to cell survival and growth. (D)</p> Signup and view all the answers

<p>Both pathways are triggered by activated Ras, but they diverge to carry out distinct cellular functions. (D)</p> Signup and view all the answers

<p>MAP kinase phosphorylates additional target proteins, amplifying and transmitting the signal to regulate cellular activities. (D)</p> Signup and view all the answers

<p>Topoisomerases help to relieve the torsional stress that builds up as the DNA helix is unwound. (C)</p> Signup and view all the answers

<p>Phosphorylation creates binding sites for signaling proteins, allowing the signal to be amplified and transmitted into the cell. (B)</p> Signup and view all the answers

<p>PCNA (C)</p> Signup and view all the answers

<p>RNase H removes RNA primers from the newly synthesized DNA strand. (B)</p> Signup and view all the answers

<p>DNA polymerases can only add nucleotides to the free 3' hydroxyl group of a growing DNA strand. (C)</p> Signup and view all the answers

<p>Necrosis involves cell swelling and membrane leakage, while apoptosis involves cell shrinkage and fragmentation. (B)</p> Signup and view all the answers

<p>DNA ligase joins the fragments of newly synthesized DNA strands together. (B)</p> Signup and view all the answers

<p>Semiconservative replication ensures that each daughter cell receives a complete set of genes. (C)</p> Signup and view all the answers

<p>RPA binds to single-stranded DNA, protecting it from damage and degradation. (A)</p> Signup and view all the answers

<p>cAMP directly binds to specific receptors on the cell membrane, triggering a cascade of events. (D)</p> Signup and view all the answers

<p>Phospholipase C activation involves a G protein, while cAMP activation of PKA does not. (A)</p> Signup and view all the answers

<p>DAG activates protein kinase C (PKC) together with calcium ions, leading to the phosphorylation of target proteins. (D)</p> Signup and view all the answers

<p>Enzyme-linked receptors have a catalytic domain, while 7TM receptors do not. (A)</p> Signup and view all the answers

<p>cAMP pathways produce a single second messenger, while phospholipase C pathways produce two second messengers with distinct functions. (B)</p> Signup and view all the answers

<p>A G protein coupled to the receptor via a second messenger molecule. (A)</p> Signup and view all the answers

<p>Enzyme-linked receptors work independently of G proteins, relying solely on their own catalytic activity. (B)</p> Signup and view all the answers

<p>All of the above are true. (D)</p> Signup and view all the answers

<p>Guanosine-5'-triphosphate (GTP) (D)</p> Signup and view all the answers

<p>Adenylyl cyclase produces cAMP, while phospholipase C generates IP3 and DAG (D)</p> Signup and view all the answers

<p>It regulates the activity of protein kinases by producing cAMP, a second messenger (C)</p> Signup and view all the answers

<p>They amplify and transmit signals inside the cell, enabling an appropriate response (B)</p> Signup and view all the answers

<p>Ligand binds to 7TM receptor → G protein is activated → adenylyl cyclase produces cAMP → target protein is phosphorylated (D)</p> Signup and view all the answers

<p>They regulate the activity of target proteins by adding phosphate groups (A)</p> Signup and view all the answers

<p>7TM receptors activate G proteins by triggering the release of GTP (D)</p> Signup and view all the answers

<p>The direct phosphorylation of target proteins by G protein subunits (B)</p> Signup and view all the answers

<p>Mitogens initiate the G1 phase of the cell cycle by triggering a cascade of events that ultimately activate kinases involved in mitosis. (A)</p> Signup and view all the answers

<p>The completion of chromosome condensation. (D)</p> Signup and view all the answers

<p>Directly modifying the structure of chromosomes during prophase. (A)</p> Signup and view all the answers

<p>These pathways transmit signals from the cell membrane to the nucleus, initiating events leading to cell division. (D)</p> Signup and view all the answers

<p>Ensuring that sister chromatids are properly aligned at the metaphase plate before separation. (A)</p> Signup and view all the answers

<p>Replication of the chromosomes to create two sets of identical chromosomes. (A)</p> Signup and view all the answers

<p>Internal regulators act as checkpoints, ensuring that the cell only progresses to the next phase when appropriate conditions are met. (D)</p> Signup and view all the answers

<p>Checkpoints act as a regulatory mechanism, determining whether the cell should proceed to the next phase of the cell cycle or undergo apoptosis. (A)</p> Signup and view all the answers

A type of protein filament that provides mechanical support to cells, with a diameter of 8-10 nm.

Protein structures about 25 nm in diameter, composed of tubulin, involved in cell transport and division.

Thin filaments 7 nm in diameter made of actin, involved in cell movement and muscle contraction.

Organelles surrounded by two membranes, including nucleus, mitochondria, and chloroplasts.

Organelles surrounded by one membrane, such as Golgi apparatus and lysosomes.

Organelles without membranes, including ribosomes, cytoskeleton, and centrosome.

A membrane-bound organelle that contains genetic information and regulates cell activities.

A network of fibers that provides structural support and shape to the cell.

Cells without a nucleus; simpler than eukaryotic cells.

Cells with a nucleus and more complex structures.

Includes the nucleus, mitochondria, and golgi apparatus.

Gel-like fluid inside a cell where organelles are found.

Compounds that contain carbon-hydrogen bonds; essential for life.

Compounds that generally do not contain C-H bonds; simpler substances.

Molecular machines that synthesize proteins in both prokaryotic and eukaryotic cells.

Explains how mitochondria and chloroplasts originated from prokaryotic cells.

All biochemical reactions in cells, vital for processes like growth and response.

Metabolic process of building complex molecules from simpler ones, requiring energy.

Metabolic process of breaking down complex molecules into simpler ones, releasing energy.

The first step of aerobic respiration that breaks glucose into pyruvic acid without ATP production.

Lipids composed of two fatty acids, glycerol, and a phosphate group, key for membrane structure.

Signaling molecules that can be activated or deactivated in response to signals.

The process of adding phosphate groups to proteins to activate them.

The removal of phosphate groups from proteins to turn them off.

Guanosine-5′-diphosphate; an inactive state of a protein when bound.

Guanosine-5′-triphosphate; an active state of a protein when bound.

Cells with two sets of chromosomes (2n), such as somatic cells.

Cells with a single set of chromosomes (1n), such as gametes.

A series of events in a cell leading to its division and DNA replication.

A process in humans where diploid cells dominate life stages and haploid cells are gametes.

A special type of cell division in germ cells that produces four haploid cells from one diploid cell.

The first division of meiosis, which reduces the chromosome number by half.

The second division of meiosis that ensures each haploid cell receives a complete chromosome set.

The longest and most complex stage of meiosis, divided into five sub-stages.

A protein structure that holds homologous chromosomes together during meiosis.

The exchange of DNA segments between non-sister chromatids during meiosis, enhancing genetic diversity.

The points where homologous chromosomes remain connected following crossing-over during meiosis.

The first phase in the cell cycle where the cell grows and prepares for DNA replication.

The phase in the cell cycle where DNA synthesis occurs, duplicating the genetic material.

Cyclin-dependent kinase inhibitors that regulate the cell cycle by inhibiting Cdks.

A group of CDKIs that includes proteins like p21 and p27 which inhibit various Cdks.

A protein that regulates cell cycle entry; increases concentration pushes cell into resting phase.

Programmed cell death that removes unnecessary or damaged cells in an organized manner.

A passive form of cell death affecting groups of cells due to damage without energy use.

A tumor suppressor that regulates the cell cycle and p27 production in response to DNA damage.

Essential chemical elements in large quantities, such as carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

Water makes up 70-80% of a living cell and acts as a solvent for chemical compounds and reactions.

Polarization in a water molecule leads to hydrogen bonds, causing molecules to group together.

A carbon atom has 6 protons, 6 neutrons, 4 valence electrons, enabling strong covalent bonds.

Compounds that consist of carbon atoms bonded to at least one other element.

Direct cell contact for signaling through surface molecules or gap junctions.

Signaling molecules released into extracellular fluid, affecting nearby cells.

Cell secretes signaling molecules that act back on itself.

Hormones secreted into the bloodstream that affect distant target cells.

Electrical and chemical signals transmitted along neurons and across synapses.

Chemicals released by neurons, including neurotransmitters and neurohormones.

Specific cells with receptors that respond to particular hormones or signaling molecules.

Proteins that detect signals and trigger cellular responses.

Transmembrane proteins that initiate signaling pathways when activated by ligands.

Molecular switches that transmit signals from 7TM receptors to target proteins.

Intracellular molecules that relay signals from G protein activation to target proteins.

Cyclic adenosine-3′,5′-monophosphate; a key second messenger in signal transduction.

An enzyme that converts ATP into cAMP upon receptor activation.

A bulk transport process for internalizing substances into a cell.

A type of endocytosis that involves the uptake of large particles like bacteria, forming a phagosome.

A form of endocytosis that allows the uptake of fluids and small solutes, creating pinosomes.

Endocytosis initiated when ligands bind to receptors on the cell membrane, forming a specialized pit.

Organelles that contain enzymes for degrading macromolecules and waste materials in cells.

Enzymes present in lysosomes that hydrolyze different biomolecules such as proteins and lipids.

A non-selective pathway for protein degradation involving lysosomes.

A selective process that degrades marked proteins using the proteasome.

The final stage of meiosis where four haploid nuclei form and chromosomes decondense.

A system that regulates the progression of the cell cycle through checkpoints.

Critical stages in the cell cycle that assess conditions for cell division.

The checkpoint between G1 and S phase that assesses cell size and DNA integrity.

Proteins that stimulate cells to divide by binding to receptors on the cell surface.

A signaling pathway activated by mitogens that promotes cell division.

Another signaling pathway linked with cell division and survival, activated by mitogens.

A second messenger involved in cellular signaling, activating protein kinase A (PKA).

An enzyme activated by cAMP that phosphorylates target proteins in response to signals.

An enzyme activated by G proteins that breaks down phosphatidylinositol to generate second messengers.

A second messenger generated by phospholipase C that triggers calcium release from the endoplasmic reticulum.

A second messenger that remains membrane-bound and helps activate protein kinase C (PKC).

Receptors that act as enzymes or bind to enzyme proteins, involved in slow signaling pathways.

A type of enzyme-linked receptor that phosphorylates tyrosine residues in response to growth factors.

Ions released by IP3 that play a crucial role in various signaling pathways and muscle contraction.

Secondary lysosomes involved in autophagy and autolysis.

Lysosomes formed by fusion with endocytosed material.

Organelles involved in detoxification and fatty acid oxidation, with a single membrane.

Process of breaking long-chain fatty acids into shorter chains within peroxisomes.

An enzyme in peroxisomes that breaks down hydrogen peroxide to prevent toxicity.

A structure near the cell nucleus, consisting of two centrioles that assist in cell division.

Cylindrical structures within the centrosome composed of microtubules, crucial for cell division.

The process of creating new peroxisomes from ER and mitochondria vesicles.

Enzymes that add phosphate groups to proteins, modifying their activity.

A checkpoint that ensures all chromosomes are properly attached to the spindle before separation.

Process where each original DNA strand serves as a template for a new complementary strand.

An enzyme that unwinds the DNA double helix during replication.

Enzymes responsible for adding nucleotides to the growing DNA strand during replication.

An enzyme that prevents DNA from becoming too twisted during unwinding.

Proliferating Cell Nuclear Antigen; a sliding clamp that keeps DNA polymerase attached to DNA.

An enzyme that removes remaining RNA fragments during DNA replication.

The process where two receptor molecules bind together to form a dimer.

The addition of phosphate groups to tyrosine residues on receptors, activating them.

A monomeric G protein activated by GTP, playing a key role in cell signaling.

A complex formed when an adaptor protein binds to Ras, exchanging GDP for GTP to activate Ras.

A series of events where kinases activate each other through phosphorylation, amplifying the signal.

The final kinase in the phosphorylation cascade that continues the signaling process.

A signaling pathway that promotes cell growth and survival upon activation by tyrosine kinases.

GTP is the active form for proteins, while GDP is the inactive form.