Hole's Human Anatomy & Physiology Chapter 3 Cells Flashcards

Flashcards covering key concepts from Hole's Human Anatomy & Physiology (2024 Release) Chapter 3 on cells, organelles, cell membrane transport, cell cycle, cancer, stem cells, and cell death.

What is the cell defined as in the human body?

The cell is the basic unit of structure and function in the body.

In what unit of measurement are cells measured?

Cells are measured in micrometers ($\mu m$).

What does it mean when cells are described as differentiated?

It means the cells have developed specialized characteristics.

What is the measured size of a disc-shaped red blood cell?

$$7.5\,\mu m$$

What is the measured size of a round white blood cell?

$$12\,\mu m$$

What is the measured size of a human egg cell?

$$140\,\mu m$$

What is the measured size of a spindle-shaped smooth muscle cell?

$$200\,\mu m$$

What are the main structural parts of a nerve cell described in the text?

A cell body with filament-like branches, a long axon, and root-like axon terminals.

What is a composite cell?

A diagrammatic representation that shows all the components found in most cells, even though no typical cell exists.

What are the three major parts of a cell?

The nucleus, cytoplasm, and cell (plasma) membrane.

What is the main function of the cell nucleus?

It contains genetic material and directs the cell's activities.

What does cytoplasm consist of?

Organelles with specific functions suspended in a liquid called cytosol.

What is the primary role of the cell (plasma) membrane?

It serves as the outer boundary of a cell, maintains cell integrity, and controls entry and exit of substances.

What is cytosol?

The fluid portion of the cytoplasm in which organelles are suspended.

What are the physical characteristics of the cell membrane?

It is flexible, thin, and elastic.

Which fluid compartments does the cell membrane separate?

It separates intracellular fluid (cytosol) from extracellular fluid.

What does it mean that the cell membrane is selectively permeable?

It regulates the entry and exit of specific substances into and out of the cell.

What is signal transduction in the context of the cell membrane?

It is the process that permits the cell to receive and respond to incoming messages.

What chemical components mainly compose the cell membrane?

Lipids and proteins, along with some carbohydrates.

What structure forms the basic framework of the cell membrane?

A phospholipid bilayer.

How are the phospholipid molecules oriented in the cell membrane bilayer?

Water-soluble (hydrophilic) polar heads form the outer surfaces, and water-insoluble (hydrophobic) nonpolar tails form the interior.

To what types of substances is the phospholipid bilayer permeable?

Lipid-soluble substances.

To what types of substances is the phospholipid bilayer impermeable?

Water-soluble substances.

What is the function of cholesterol in the cell membrane?

It stabilizes the membrane and helps keep it impermeable to water-soluble substances.

Why is the cell membrane described as having "fluid mosaic" properties?

Because some of its constituent lipids and proteins can move within the membrane structure.

What are the primary functions of carbohydrates in the cell membrane?

Cell recognition and interaction, and acting as self markers.

What is the function of receptor proteins in the cell membrane?

They respond to extracellular signals.

What is the function of pores, channels, and carriers in the cell membrane?

They transport small molecules and ions, and transduce signals.

What is the function of enzymes embedded in the cell membrane?

They catalyze chemical reactions.

What is the function of cell surface proteins in the cell membrane?

They establish self identity for the cell.

What is the function of Cellular Adhesion Molecules (CAMs)?

They enable cells to stick to each other and guide cells on the move.

What clinical condition results from mutations in Sodium ($\text{Na}^+$) channels?

Inability to feel pain or extreme pain conditions.

What clinical conditions result from mutations in Potassium ($\text{K}^+$) channels?

Disruption of electrical activity of the heart (disturbed heart rhythm) and/or impaired hearing.

Abnormal Chloride ($\text{Cl}^-$) channels are the cause of which clinical disease?

Cystic Fibrosis.

What symptoms characterize Cystic Fibrosis?

Production of thick mucus causing difficulty breathing, a clogged pancreas, and salty sweat.

What is the specific role of selectins during cell adhesion?

They coat white blood cells and anchor them to capillary walls by providing friction.

What is the role of adhesion receptor proteins during cell adhesion?

They bind to integrins to help white blood cells leave the capillary.

What is the role of integrins during cell adhesion?

They direct white blood cells through capillary walls toward infection sites.

What are two additional functions of Cellular Adhesion Molecules (CAMs) besides guiding white blood cells?

Guiding embryonic cells toward maternal cells to form the placenta, and establishing connections between nerve cells.

What are the three steps in white blood cell extravasation shown in Figure 3.7?

1) Attachment (rolling), 2) Adhesion, and 3) Exit.

What constitutes cytoplasm?

Networks of membranes and organelles suspended in cytosol (Cytoplasm = cytosol + organelles).

What is the cytoskeleton?

A supporting framework of protein rods and tubules contained within the cytoplasm.

What chemical components form ribosomes?

Protein and RNA.

Where are ribosomes located within a cell?

Free in the cytoplasm or attached to the Rough Endoplasmic Reticulum (RER).

What is the primary function of ribosomes?

They provide structural support and enzymatic activity to link amino acids in protein synthesis.

What is the Endoplasmic Reticulum (ER)?

A complex system of membrane-bound sacs, canals, and vesicles that functions as a tubular transport system.

How do Rough ER and Smooth ER differ structurally and functionally?

Rough ER contains ribosomes and conducts protein synthesis; Smooth ER lacks ribosomes and conducts lipid synthesis.

What are vesicles?

Membranous sacs that store or transport substances within the cell.

What is the structural description of the Golgi apparatus?

Stacks of flattened, membranous sacs.

What is the main function of the Golgi apparatus?

It refines, packages, and delivers proteins made on the Rough ER.

Where are milk fats synthesized during milk secretion?

In the smooth endoplasmic reticulum (SER).

Where are most milk proteins synthesized during milk secretion?

On ribosomes associated with membranes of the rough endoplasmic reticulum (RER), using amino acids in the cytosol.

Where are sugars synthesized during milk secretion?

In the smooth ER and Golgi apparatus.

How are proteins released from the cell during milk secretion?

They are secreted from vesicles that bud off of the Golgi apparatus.

How do fat droplets pick up a membrane layer as they exit the cell during milk secretion?

They pick up a layer of the cell membrane as they exit the cell.

What is the structural description of mitochondria?

Membrane-bound, fluid-filled sacs with transverse inner membrane folds called cristae.

What chemical reactions are housed inside mitochondria?

Cellular respiration reactions that extract energy from nutrients to produce ATP.

What common name is given to mitochondria?

The "powerhouse of the cell".

What are lysosomes and what do they contain?

Small membranous sacs containing enzymes that digest proteins, carbohydrates, nucleic acids, bacteria, debris, and worn-out cell parts.

What informal title is given to lysosomes?

The "garbage disposals" of the cell.

What are peroxisomes and what do their enzymes digest?

Membranous sacs containing enzymes that digest lipids, alcohol, and hydrogen peroxide ($\text{H}_2\text{O}_2$).

What three types of thread-like structures compose the cytoskeleton?

Microfilaments, microtubules, and intermediate filaments.

What are microfilaments composed of and what is their relative diameter?

They are tiny rods of actin and have the smallest diameter among cytoskeletal filaments.

What is the primary function of microfilaments?

They provide cellular movement, such as muscle contraction.

What are microtubules composed of and what is their relative diameter?

They are tubes of tubulin and have the largest diameter among cytoskeletal filaments.

What structures are formed by microtubules and what is their functional role?

They maintain cell shape, help move organelles, and make up cilia, flagella, and centrioles.

What is the structural role of intermediate filaments?

Composed of several proteins with an intermediate diameter, they support the nuclear envelope.

What is the centrosome?

A "central body" in the cytoplasm near the nucleus consisting of two centrioles.

What is the function of centrioles during cell division?

They produce spindle fibers that distribute chromosomes to the forming daughter cells.

What are cilia?

Motile extensions of the cell membrane consisting of microtubules in a cylindrical pattern that form a "fringe" on certain epithelial cells.

What are two physiological functions of cilia mentioned in the transcript?

Propelling mucus in the respiratory tract and propelling an egg toward the uterus.

What two stroke patterns do cilia exhibit during movement?

The power stroke and the recovery stroke.

What is a flagellum and where is the only flagellum located in a human cell?

A long motile extension from the cell membrane that moves the entire cell; the tail of a sperm cell is the only flagellum in a human cell.

What are microvilli composed of?

Actin.

What is the primary function of microvilli?

To increase surface area for absorption.

What are cell inclusions?

Chemical substances present only in some cell types that are not necessary for cell survival, such as melanin granules or fat.

What causes MELAS and what is its outcome?

A mutant gene in mitochondrial DNA, preventing a person from extracting maximum energy from nutrients.

What causes Krabbe Disease and what damage does it inflict?

Inability to produce one lysosomal enzyme, preventing myelin production for nerve cells and causing severe nervous system damage.

What causes Adrenoleukodystrophy (ALD) and what are its symptoms?

Lack of a protein in peroxisome membranes causing fatty acid buildup that destroys myelin sheaths, slowing nerve impulse transmission.

What is the structure and function of the nuclear envelope?

A double-layered membrane that surrounds the nucleus, separates nucleoplasm from cytoplasm, and contains nuclear pores for substance transport.

What is the nucleolus and what process occurs there?

A dense body of RNA and protein inside the nucleus that serves as the site of ribosome production.

What is chromatin?

A structure consisting of cell chromosomes (DNA wound around proteins) that stores information for protein synthesis.

What distinguishes physical (passive) movement mechanisms from active mechanisms?

Physical mechanisms do not require cellular energy (ATP), whereas active mechanisms require ATP.

Which four movement processes are classified as physical (passive) mechanisms?

Diffusion, facilitated diffusion, osmosis, and filtration.

What is diffusion?

Movement of atoms, molecules, or ions from a region of higher concentration to a region of lower concentration.

What causes the process of diffusion to occur?

The constant motion of atoms, molecules, and ions.

What types of substances can pass through the cell membrane by simple diffusion?

Substances to which the membrane is permeable, such as oxygen, carbon dioxide, and other lipid-soluble substances.

What state is reached when water and solute concentration becomes equal on both sides of a membrane?

Equilibrium.

What is facilitated diffusion?

Diffusion across the cell membrane through membrane proteins, such as ion channels or transporters (carriers).

Which types of substances require facilitated diffusion to cross the cell membrane?

Water-soluble substances that are not lipid-soluble, such as glucose and amino acids.

Is facilitated diffusion an active or passive transport mechanism?

It is a passive transport mechanism; no ATP is required.

What is osmosis?

Movement of water across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

What specialized water channels facilitate osmosis across the cell membrane?

Aquaporins.

What is osmotic pressure?

The ability of osmosis to generate enough pressure to lift a volume of water.

How does impermeant solute concentration affect osmotic pressure?

Osmotic pressure increases as the concentration of impermeant solutes increases in a solution.

What is tonicity?

The ability of a solution outside a cell to alter water volume inside the cell.

What happens to a cell placed in an isotonic solution?

The cell experiences no net gain or loss of water because the osmotic pressure is equal inside and outside.

What happens to a red blood cell placed in a hypertonic solution?

Water moves by osmosis out of the cell into the hypertonic solution, resulting in cell shrinkage (crenation).

What happens to a red blood cell placed in a hypotonic solution?

Water enters the cell by osmosis, causing the cell to swell or even burst (lyse).

What is filtration?

A passive process that forces molecules through membranes by exerting pressure.