BIO 105: A & P CH 5 - 6 Structure of the cell and the functions

Flashcards containing vocabulary terms and definitions from the lecture notes.

Plasma Membrane

Separates the internal environment of the cell from the external environment; selective barrier that regulates the flow of materials into and out of the cell.

Structure of the Plasma Membrane

Made of phospholipid bilayer; lipid soluble materials pass through while water cannot.

Fluid-Mosaic Model

Resembles a continually moving sea of lipids that contains a mosaic of many different proteins; Lipids allow passage of lipid soluble molecules but act as a barrier to the entry or exit of all other molecules.

Receptor Proteins

React to the presence of certain substance (such as hormones) and allows that protein to open.

Ion Channels

Pores or holes that specific ions (such as K+) can flow through to get in or out of the cell.

Glycoprotein

Cell identification markers.

DNA

Genetic material- contains the “blueprint” for the body.

Chromosomes

DNA that has been coiled into an “X” shape.

Cytosol

Gel-like substance inside cells; fluid portion of the cytoplasm the surrounds organelles; where many chemical reactions take place.

Ribosomes

Contain ribonucleic acid (RNA); Function: protein synthesis or “protein factories”.

Endoplasmic Reticulum (ER)

Canals and flat, curving sacs in parallel rows.

Golgi Apparatus (GA)

Processes and packages protein molecules from the rough ER.

Vesicle

Used by ER and GA to transport molecules.

Lysosomes

Vesicles (membranous sacs) that have been pinched off by the GA; contain enzymes to protect cells, help break down proteins that are not needed.

Proteasomes

Protein-destroying organelle that targets and destroys abnormal proteins from the rough ER.

Peroxisomes

Membranous sacs containing enzymes; detoxify harmful substances; found mostly in liver and kidney cells.

Mitochondria

Powerhouse of the cell; enzymes make ATP (adenosine triphosphate).

Cytoskeleton

Internal supporting framework of the cell, allows for support and movement of the cell.

Microfilaments

Smallest cell fibers; help to generate cellular movement and provide mechanical support.

Intermediate Filaments

Slightly thicker than microfilaments; found in cells subject to mechanical stress; stabilize position of organelles within cell.

Microtubules

Thickest cell fibers; long, hollow tubes; form “cellular roads”.

Centrosomes

Region of cytoplasm near nucleus that coordinate the building and breaking of microtubules in the cell; play a role in cell division by moving chromosomes around cell.

Microvilli

Typically found in areas of absorption, increase surface area.

Cilia

Hair like structures; Example: respiratory tract: maintain mucus membrane.

Flagella

Single long tail like structure; Example: only in human sperm cell; allows to “swim” toward egg cell.

Desmosomes

Velcro-like fibers on the outer surface of each lock with each other; anchored internally by intermediate filaments within the cell.

Gap Junctions

Membrane channels of adjacent plasma membranes which adhere to one another forming tunnels; molecules and electrical impulses can pass directly from one cell to another.

Tight Junctions

Membrane proteins fuse with adjoining cell membrane proteins; limit passage of materials between cells.

Permeable

Permits the passage of substances through the membrane.

Impermeable

Structure does not permit the passage of substances through the membrane.

Selective Permeability

Plasma membrane permits the movement of some substances but not others.

Concentration Gradient

Difference in concentration of a chemical from one place to another.

Diffusion

Molecules move from an area of high concentration to an area of low concentration.

Simple Diffusion

Passive process in which substances move freely through the lipid bilayer of the plasma membrane of cells without the help of membrane proteins.

Dialysis

Diffusion of solutes through a selectively permeable membrane.

Osmosis

Diffusion of solvent (water) through a selectively permeable membrane.

Isotonic Solution

Two fluids that have the same osmotic pressure, no chance in cell.

Hypertonic Solution

High solutes, leads to a “crenated” cell.

Hypotonic Solution

Low solutes, leads to “lysis” cell.

Facilitated Diffusion

Membrane proteins which allow the movement of specific ions or small molecules to pass.

Filtration

Water solutes move through a membrane by hydrostatic pressure.

Hydrostatic Pressure

Force or weight of a fluid pushing against a surface.

Active Transport

Cellular energy is used to drive the substance “uphill” against its concentration gradient.

Primary Active Transport

Energy derived from ATP “pumps” a substance across the plasma membrane.

Endocytosis

Plasma membrane traps extracellular material to enter the cell.

Phagocytosis

Form of endocytosis where a cell engulfs large solid particles, such as worn out cells, whole bacteria, or viruses.

Pinocytosis

Form of endocytosis in which tiny droplets of extracellular fluid are taken up.

Exocytosis

Process by which large molecules (proteins) leaves the cell.

Transcytosis

Used to successively move a substance into, across, and out of the cell.

Catabolism

Metabolism that breaks down molecules, typically to release energy.

Cellular Respiration

Glucose is broken down to yield its stored energy.

Glycolysis

Pathway in which glucose is broken apart into two pyruvic acid molecules to yield a small amount of energy.

Citric Acid Cycle

Occurs in the mitochondria; aerobic respiration- requires oxygen.

Electron Transportation Chain

Occurs in the mitochondria; aerobic respiration- requires oxygen.

Anabolism

Metabolism that builds large molecules from smaller ones; consumes energy.

Protein Synthesis

Where cells use its DNA to create proteins.

Transcription

Information encoded in specific region of DNA is transcribed (copied) to produced a specific molecule of RNA; this occurs in the nucleus.

Translation

The RNA then attaches to a ribosome in the RER, where the information contained in the RNA is translated to form a new protein.