APHY 101 Ch. 3 Terms Flashcards
Micrometer
A unit of measurement that equals one thousandth of a millimeter and is symbolized μm
Differentiated cells
Cells with specialized characteristics that form from less specialized cells that divide and express specific genes.
Cell’s Major Parts
- Nucleus (enclosed by the nuclear envelope)
- Cytoplasm
- Cell Membrane
Nucleus
Contain genetic material (DNA) which directs the cell’s functions
Cytoplasm
Found within the cell membrane; the protoplasm within a living cell that surrounds the nucleus.
Cytosol
The aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended.
Cytosol Organelles
The cytosol and organelles together compose the cell’s cytoplasm. Most organelles are surrounded by a lipid membrane similar to the cell membrane of the cell.
Cell Membrane
Mainly composed of roughly equal numbers of lip and protein molecules, with fewer carbohydrates.
Extremely thin. Maintains cell’s integrity. Controls the entrance and exit of substances.
Selectively Permeable
A membrane that controls the entrance and sit of substances , allowing some in while excluding others.
Signal Transduction
A process in which the cell is able to receive and respond to incoming messages via the cell membrane and extracellular fluids.
Bilayer
The basic framework of the cell membrane that is a double layer of phospholipid molecules that self-assemble so that their hydrophilic, phosphate containing “heads”, form the intracellular and extracellular surfaces of the membrane while the hydrophobic, fatty acid containing “tails”, make up the middle portion of the cell membrane.
Membrane Proteins
Provide specialized functions. They are classified by shape, their positions within the phospholipid bilyarer, and function.
May be shaped like globs, rods, or fibers.
Based on position, may be considered as integral or peripheral.
Receptors
Transmembrane proteins that are tightly coiled rods. They bind to specific incoming molecules such as hormones, triggering responses from within the cell.
Integral Protein
Extends into the lipid bilayer and may protrude from one or both sides.
Form pores, channels, and carries in the cell membrane; transduce signals.
Transmembrane Protein
An integral protein that extends through both sides of the lipid bilayer.
Peripheral Protein
Associate with one side of the lipid bilayer, from an outside attachment rather than being embedded within it.
Receptor Protein
Peripheral.
Respond to extracellular signals.
Cell Surface Proteins
Establish self
Cellular Adhesion Molecules
Enable cells to stick to each other, guide cells on the move.
Selectin
A type of cellular adhesion molecule that coats the white blood cell and provides traction to slow down.
Integrin
A type of cellular adhesion molecule that contacts and adhesion receptor protein protruding into the capillary cell membrane, grabbing the passing slowed white blood cell and directing it between the tile like cells of the capillary wall.
Inclusion
Chemicals found with the cytoplasm temporarily. These include stored nutrients (ie; glycogen and lipids), and pigments (ie; melanin).
Cytoskeleton
Protein rods and tubules that form a supportive framework in the cytoplasm.
Characteristics of vesicles
- contains substances that have just entered the cell
- contain substances that have been produced by other organelles
- are membranous sacs
Cellular energy
the source of energy for active transport mechanisms
Ribosomes
- Tiny, spherical structures composed of protein and RNA
- They provide structural support and enzymatic activity to like amino acids to synthesize proteins
- Scattered in the cytoplasm and bound to the endoplasmic reticulum
Endoplasmic Reticulum
- A complex organelle composed of membranous flattened-sacs, cylinders and fluid-filled bubble like sacs called vesicles that are interconnected and interact with the cell membrane, nuclear envelope and certain other organelles.
- Widespread in the cytoplasm; providing tubular transport for molecules throughout the cell
- Parts participate in the synthesis of protein and lips molecules
Rough Endoplasmic Reticulum
- Part of the ER where the outer surface is studded with many ribosomes that provide a textured appearance to the organelle.
Smooth Endoplasmic Reticulum
- Part of the ER where the surface lacks ribosomes; it appears more cylindrical.
- Along this part of the ER are enzymes that are important in synthesizing lipids, absorbing fats from the digestive tract, and breaking down certain drugs.
- Especially abundant in liver cells to help break down alcohol and drugs
Vesicles
- Membranous sacs that store or transport substances within a cell or between cells.
- Vary in size and contents.
- Larger: contain mostly water
- Smaller: shuttle material from the rough ER to the Golgi as part of secretion
Vesicle Trafficking
The transport of substance into and out of the cells by fleets of vesicles
Golgi Apparatus
- A stack of five to eight flattened, membranous sacs called cistern (stack of pancakes).
- Refines, packages, and transports proteins synthesized in the rough ER
- Glycoproteins pass from layer to layer through these stacks and may be chemically modified and packaged to move to the cell membrane – exocytosis
Diffusion
Exchange of oxygen and carbon dioxide in the lung
Facilitated Diffusion
Movement of glucose through a cell membrane
Osmosis
Distilled water entering cell
Filtration
Water molecules leaving blood capillaries
Active Transport
Sodium potassium pump
Ribosome
Site of protein synthesis
Cytoskeleton
Three parts:
- Microfilament
- Intermediate Filaments
- Microtubule
Nucleus
Surrounded by an envelope and contains genetic material
Transport Mechanisms that are classified as Passive mechanisms
- diffusion
- facilitated diffusion
- filtration
- osmosis
Components of the cell membrane
- phospholipids
- carbohydrates
- cholesterol
- proteins
Proteins in the cell membrane
Function as: receptors, cell surface markers, transporters, channels, enzymes, and cellular adhesion molecules
Filtration
The passive transport mechanism in which small solutes are forced through a membrane by hydrostatic pressure
Phagocytosis
The process by which cells engulf solid particles from extracellular fluid
Transport mechanism classified as active mechanisms
- active transport
- exocytosis
- endocytosis
Golgi Apparatus
Packages and modifies proteins for transport and secretion
Four stages of mitosis
Prophase, Anaphase, Metaphase and Telophase
Active transport
substances are moved across a membrane against the concentration gradient
Diffusion
Movement of molecules through the bilayer and down a concentration gradient
Osmosis
Movement of water through a selectively permeable membrane towards a solution with greater osmotic pressure
Endocytosis
- The process of the cell taking particles in with use of a vesicle
- The type of active transport mechanism in which large molecules or particles are conveyed by a vesicle into the cell
Exocytosis
The process of the cell releasing contents from a vesicle to outside the cell
Active Transport
Movement of molecules against the concentration gradient with the use of a protein pump
Flagella
- Longer
- Function to move the cell in the body
- Usually only one
Cilia
- Shorter
- Function to move substance across the cell surface
- Multiple on one cell
Concentration gradient
Refers to the difference in concentration between two regions
Characteristics of the ER
- provides attachment for ribosomes
- functions in the synthesis of proteins
- function in the synthesis of lips
- composed of membranous sacs
Found in the cytoplasm
- cytoskeleton
- organelles
- cytosol
Molecules moving down a concentration gradient
When molecules move from a region of higher concentration to a region of lower concentration
Facilitated Diffusion
The passive transport mechanism in which molecules or ions move via carrier proteins from a region of higher concentration to a region of lower concentration
Simple Diffusion
Occurs due to the random movement of atoms, molecules, or ions in air or liquid, from areas of higher concentration to areas of lower concentration
Nucleolus
Found within the nucleus and functions to produce ribosomes
Cell cycle
The series of changes that a cell undergoes from the time it forms until the time it finishes dividing.
Phagocytosis Sequence of Events
- An engulfed particle is enclosed within a vesicle
- A vesicle detaches from the cells surface and moves into the cell’s interior
- Vesicle-lysosome fusion occurs
- Digestive lysosomal enzymes decompose vesicle contents
- Products of intracellular digestion diffuse into the cytoplasm
- Residues are expelled outside through exocytosis
Characteristics of vesicles
- contain substances that have been produced by other organelles
- contain substances that have just entered the cell
- are membranous sacs
Mitochondrion
This organelle is known as the “powerhouse of the cell” as it captures and transfers newly released energy into special chemical bonds of adenosine triphosphate (ATP).
Organelle
A specialized structure inside a cell that performs specific functions such as extracting energy from nutrients or building proteins
Basic framework of the cell membrane
A bilayer of phospholipid molecules.
Stem Cell
An undifferentiated cell that can divide
Meiosis
- The form of cell division that occurs only in cells that give rise to sex cells.
- Reduction of the chromosome number, as needed to produce sex cells (gametes) such as sperm and egg cells
Mitosis
- Nuclear division, producing two daughter nuclei with the same DNA make-up as the original cells.
- Occurs in somatic cells.
Function of glycoproteins
To identify the cell as being “self” or foreign
Function of integral proteins
- Transduce signals across the membrane
- Transport molecules across the membrane
Characteristics of Chromatin
- made of protein and DNA
- Condenses into chromosomes during cell division
Three main stages of the cell cycle
Interphase, mitosis (division of the nucleus), and cytokinesis (division of the cytoplasm)
Three function of proteins in the cell membrane
- receptors to bind chemicals
- adhere adjacent cells to each other
- channels for ions to move through
Sub-phases of interphase
- S
- G1
Two organic molecules that the ER play a role in synthesizing
- Proteins
- Lipids
Interphase
The active period of the cell cycle, during which a cell grows, DNA replicates, and new organelle form. It terminates when the cell begins mitosis.
Ions are hydrophilic, and therefore cannot cross the plasma membrane without help from what structures:
- ion channels
- integral proteins
Integral protein
a type of compact or globular protein that spans the cell membrane
Meiosis
Occurs in sperm and egg cells and produces four daughter cells.
Transmembrane integral proteins that act as pores or channels allow what type of molecules to cross the cell membrane:
- ions
- water
Chromatin
The material in the nucleus that is composed of protein and DNA: it contains information to guide synthesis of proteins and it condenses into chromosomes during cell division.
Prophase
During this phase:
- Chromatin condenses into chromosomes
- Centrioles move to opposite sides of the cell
- Spindle fibers form as the centrioles move apart
- The nuclear envelope and nucleolus disperse.
Filtration
A solution is pushed through a membrane by a force called hydrostatic pressure. This is a passive transport mechanism.
How many chromosomes are in each new cell after mitotic divisions?
2 sets of 23 chromosomes: 46 chromosomes total
Peripheral protein
A type of protein in the cell membrane that does not span the entire membrane: instead, it projects from one side only of the membranes surface
Interphase
The phase that begins after cytokinesis and ends at prophase
Cytokinesis
- Cell membrane constricts around center of the cell
- The cytoplasm is divided between the cells
Characteristics of the Cell membrane
- it enables communication and interaction
- it functions as a boundary for the cell
- it carries out important metabolic reactions
Differentiation
process of specialization in which cells specialize to form adult cells
Active Transport Mechanism
- exocytosis
- transcytosis
- pinocytosis
Lysosomes
Organells that are membranous sacs containing powerful digestive enzymes
Glycoproteins
Molecules within the cell membrane that function in cell recognition
Characteristics of phagocytosis
- a line of defense against infection
- allows the body to remove damaged cells
- it is an active transport mechanism
Apoptosis
a form of “programmed cell death” and is a normal part of development.
Diffusional equilibrium
occurs when the concentration of a given substance becomes uniform throughout a solution and there is no further net movement of molecules throughout the solution.
Nuclear envelope
Perforated with openings called nuclear pores that regulate the movement of molecules through the structure
- separates the nuclear contents from the cytoplasm
- a double-layered porous membrane
Isotonic solution
has the same osmotic pressure as body fluids
