Applied Physiology: Cell Physiology (2)

What are the three major parts of a cell?

Plasma membrane, nucleus, and cytoplasm.

What is the plasma membrane?

The thin, oily, fluid membrane surrounding the cell that separates intracellular fluid (ICF) from extracellular fluid (ECF) and selectively controls movement of substances into and out of the cell.

What is intracellular fluid (ICF)?

Fluid located inside cells.

What is extracellular fluid (ECF)?

Fluid located outside cells.

What is cytoplasm?

Everything between the plasma membrane and nucleus; consists of cytosol, organelles, and cytoskeleton.

What is cytosol?

The semiliquid portion of the cytoplasm that surrounds the organelles.

What is the nucleus?

The cell's control center that contains DNA.

What is the nuclear envelope?

A double-layered membrane surrounding the nucleus.

What are nuclear pores?

Openings in the nuclear envelope that allow selected materials to move between the nucleus and cytoplasm.

What is DNA?

Deoxyribonucleic acid; the cell's genetic material containing instructions for making proteins and controlling cellular activities.

What is a chromosome?

A structure composed of DNA and associated proteins that contains genes.

What is gene expression?

The process of using the information contained in a gene to produce a functional product, usually a protein.

What is RNA?

Ribonucleic acid; it helps use genetic information from DNA for protein production.

What does messenger RNA (mRNA) do?

Messenger ribonucleic acid carries genetic instructions copied from DNA to the ribosome.

What does ribosomal RNA (rRNA) do?

Ribosomal ribonucleic acid combines with proteins to form ribosomes.

What does transfer RNA (tRNA) do?

Transfer ribonucleic acid carries specific amino acids to the ribosome during protein synthesis.

What is the genome?

The complete set of an organism's genetic material or DNA.

What is the proteome?

The complete set of proteins expressed by a cell or organism at a particular time.

What is epigenetics?

Changes in gene expression without changing the DNA sequence itself.

What is the lipidome?

The complete collection of lipids within a cell or organism.

What is an organelle?

A specialized structure within a cell that performs a particular cellular function.

What is the difference between membranous and nonmembranous organelles?

Membranous organelles are surrounded by a membrane; nonmembranous organelles are not.

What is the endoplasmic reticulum (ER)?

An interconnected membranous network involved in the production, processing, and transport of cellular materials.

What is rough endoplasmic reticulum (rough ER)?

Endoplasmic reticulum with ribosomes attached; primarily involved in protein production.

What is smooth endoplasmic reticulum (smooth ER)?

Endoplasmic reticulum without ribosomes; involved in functions such as lipid synthesis and detoxification.

What is a ribosome?

A nonmembranous structure that synthesizes proteins.

What is the difference between free and attached ribosomes?

Free ribosomes float in the cytosol; attached ribosomes are attached to rough endoplasmic reticulum.

What is a transport vesicle?

A small membrane-bound sac used to transport materials between cellular locations, such as from the endoplasmic reticulum to the Golgi apparatus.

What is ubiquitin?

A protein that tags unwanted or damaged proteins for destruction.

What is a proteasome?

A nonmembranous protein complex that degrades proteins tagged with ubiquitin.

What is the Golgi apparatus?

A membranous organelle that modifies, sorts, packages, and directs proteins and other products.

What is the purpose of docking markers and docking acceptors?

They allow transport vesicles to recognize and dock with the correct target membrane.

What is a V-SNARE?

A vesicle-associated docking protein that helps a vesicle recognize and fuse with its correct target membrane.

What do coat proteins do during vesicle formation?

They help shape the membrane and form a budding vesicle.

What is budding?

The process in which part of a membrane bulges outward and pinches off to form a vesicle.

What is a secretory vesicle?

A membrane-bound vesicle containing substances that will be released from the cell.

What is secretion?

The release of substances produced by a cell into the extracellular environment.

What is a lysosome?

A membrane-bound organelle containing digestive enzymes that break down materials and worn-out cellular components.

What is endocytosis?

Movement of substances into a cell by formation of membrane-bound vesicles.

What is pinocytosis?

Nonspecific uptake of extracellular fluid and dissolved substances into a cell.

What is receptor-mediated endocytosis?

Selective uptake in which a substance binds to a specific membrane receptor before being brought into the cell.

What is phagocytosis?

A process in which a cell engulfs large particles, such as microorganisms or cellular debris.

What are pseudopods?

Temporary extensions of the cell used for movement and engulfing particles during phagocytosis.

What is a phagosome?

A membrane-bound vesicle containing material that has been engulfed through phagocytosis.

What is autophagy?

The lysosomal process of breaking down and recycling worn-out or damaged parts of the cell.

What is a peroxisome?

A membrane-bound organelle containing oxidative enzymes involved in detoxification.

What are oxidative enzymes in peroxisomes used for?

They carry out oxidation reactions involved in detoxifying harmful substances.

What does catalase do?

Catalase helps convert harmful hydrogen peroxide (H2O2) into less harmful products.

What is the major function of mitochondria?

To extract energy from nutrients and convert it into a usable form, primarily adenosine triphosphate (ATP).

What are cristae?

Folds of the inner mitochondrial membrane that contain proteins involved in electron transport and ATP production.

What is the mitochondrial intermembrane space?

The space located between the outer and inner mitochondrial membranes.

What is the mitochondrial matrix?

The innermost mitochondrial compartment where the citric acid cycle occurs.

What is a mitochondrial reticulum?

An interconnected network of mitochondria present in some cell types.

What does ATP stand for?

Adenosine triphosphate.

What is the major role of ATP?

ATP provides immediately usable energy for cellular activities.

What does ADP stand for?

Adenosine diphosphate.

What happens when ATP is broken down?

ATP becomes ADP plus inorganic phosphate (Pi), releasing energy.

What is cellular respiration?

The processes through which cells extract energy from nutrients and use it to produce ATP.

What are the three stages of cellular respiration?

Glycolysis, citric acid cycle, and oxidative phosphorylation.

Where does glycolysis occur?

In the cytosol.

What happens during glycolysis?

One 6-carbon glucose molecule is split into two 3-carbon pyruvate molecules, producing 2 ATP and electron carriers.

What happens to pyruvate before entering the citric acid cycle?

Pyruvate is converted into an acetyl group, which combines with coenzyme A to form acetyl-CoA (acetyl coenzyme A).

Where does the citric acid cycle occur?

In the mitochondrial matrix.

What are three names for the same metabolic cycle?

Citric acid cycle, Krebs cycle, and tricarboxylic acid (TCA) cycle.

What happens to the acetyl group during the citric acid cycle?

Its carbons are eventually released as carbon dioxide while energy is captured in electron carriers and a small amount of ATP is produced.

What does NAD+ stand for?

Nicotinamide adenine dinucleotide.

What happens when NAD+ accepts high-energy electrons or hydrogen?

It becomes NADH, the electron-carrying form.

What does FAD stand for?

Flavin adenine dinucleotide.

What happens when FAD accepts high-energy electrons or hydrogen?

It becomes FADH2, an electron-carrying form.

What do NADH and FADH2 do?

They carry high-energy electrons to the electron transport system for ATP production.

What is oxidative phosphorylation?

The stage of cellular respiration in which energy from electrons establishes a hydrogen-ion gradient that drives ATP production.

Where does oxidative phosphorylation occur?

Along the inner mitochondrial membrane or cristae.

What happens in the electron transport system?

High-energy electrons are passed from carrier to carrier, releasing energy used to pump hydrogen ions (H+) from the matrix into the intermembrane space.

What is the final electron acceptor in the electron transport system?

Oxygen (O2).

What happens to oxygen at the end of electron transport?

Oxygen accepts electrons and combines with hydrogen ions (H+) to form water.

What does the hydrogen-ion gradient accomplish?

Hydrogen ions flow back into the matrix through ATP synthase, providing energy to produce ATP.

What is chemiosmosis?

Movement of hydrogen ions (H+) down their gradient through ATP synthase, driving ATP formation.

Approximately how much ATP does the PowerPoint account for from one glucose molecule?

32 ATP total: 2 from glycolysis, 2 associated with the citric acid cycle, and 28 from oxidative phosphorylation.

What is aerobic metabolism?

Energy metabolism that occurs when oxygen is available, allowing the cell to obtain a much larger ATP yield.

What is anaerobic metabolism?

Energy metabolism used when insufficient oxygen is available, causing greater reliance on glycolysis.

What happens to pyruvate during anaerobic metabolism?

Pyruvate is converted to lactate.

Why does anaerobic metabolism produce much less ATP than aerobic metabolism?

The cell can continue glycolysis but cannot obtain the large ATP yield from oxygen-dependent oxidative phosphorylation.

What is apoptosis?

Programmed cell death.

How are mitochondria involved in apoptosis?

Cytochrome c can leak from mitochondria into the cytosol and activate enzymes that break down the cell.

What are vaults?

Nonmembranous organelles thought to participate in transporting molecules between the nucleus and cytoplasm; their exact function is not completely understood.

What is intermediary metabolism?

The interconnected chemical reactions within cells that process nutrients for use, conversion, or storage.

What cellular activities does the PowerPoint associate with the cytosol?

Enzymatic regulation of intermediary metabolism, ribosomal protein synthesis, and storage of fat, carbohydrate, and secretory vesicles.

What are inclusions?

Stored materials within the cytosol, such as fat droplets and glycogen granules.

How is fat stored in the cells shown in the PowerPoint?

As fat droplets in adipose cells.

How is carbohydrate stored in the cells shown in the PowerPoint?

As glycogen granules in liver cells.

What is the cytoskeleton?

The cell's internal structural framework responsible for shape, rigidity, organization, intracellular transport, and cellular movement.

What are the three major components of the cytoskeleton?

Microtubules, microfilaments, and intermediate filaments.

What protein makes up microtubules?

Tubulin.

What are major functions of microtubules?

Intracellular transport, formation of the mitotic spindle, and structural support for cilia and flagella.

What is kinesin?

A motor protein that transports cargo such as vesicles along microtubules.

What is the mitotic spindle?

A microtubule structure that helps separate duplicated chromosomes during mitosis.

What is mitosis?

Nuclear division in which duplicated chromosomes are separated into daughter nuclei.

What are centrioles?

Structures that help organize microtubules, including those involved in the mitotic spindle.

What are cilia?

Numerous short cell-surface projections containing microtubules that beat to move material across the cell surface.

What are flagella?

Longer cell-surface projections containing microtubules that propel the entire cell.