Chapter 3 Cellular Form And Function Flashcards
Cell
Basic, living, structural, functional unit of the body
Cytology
Study of cell structure
Cell physiology
Study of cell function
Squamous shape
Thin, flat, scaly
Cuboidal shape
Square, cube
Columnar shape
Taller than wide
Polygonal shape
Irregular
Stellate shape
Star-like
Spheroid/ovoid shape
Round to oval
Discoidal shape
Disk like
Fusiform shape
Thick in middle
Fibrous shape
Thread like
Plasma membrane/ cell membrane
Flexible barrier that surrounds the cytoplasm of the cell, the membrane consists of a sea of lipids with proteins afloat
Cytoplasm
Liquid that fills inside of cell
Cytosol
Fluid portion
Organelles
Internal cellular structures other than the nucleus
Nucleus
Contains DNA or genetic material
intracellular fluid (ICF)
The fluid within the body cells
Extracellular fluid (ECF)
The fluid outside of body cells
Interstitial fluid
ECF filling the narrow spaces between tissues
Plasma
ECF in blood vessels
Functions of the plasma membrane
-physical barrier
-Regulation of exchange of molecules and ions with the environment
-sensitivity to the environment
-structural support
98% on membrane molecules are:
Lipids
Phospholipid bilayer
The basic framework of the cell membrane
How do the phospholipids orient themselves within the bilayer?
By positioning themselves with the hydrophilic heads directed outwards and the hydrophobic tails directed inwards
Integral proteins
Embedded proteins in the plasma membrane that are exposed of ECF and/or ICF on one or both sides
Transmembrane proteins
Integral proteins that pass completely through the phospholipid bilayer
Peripheral proteins
Proteins loosely attached to either the inside or outside of the plasma membrane
Glycoproteins
Integral or peripheral proteins that have chains of sugar molecules attached to them located on the outside surface of the plasma membrane
Glycocalyx
Carbohydrate enriched coat formed by glycoproteins and glycolipids around the outside of the cell
Functions of glycocalyx
-act as signature sequence that allow cells to recognize one another
-adherence
-protection from digestion
-attracts water molecules
Receptor protein
Binds to chemical messengers, change inside the cell happens
Enzymes protein
Catalyzes reactions inside or outside of cell
Leakage channel protein
Allows polar molecules into cell, constantly open
Gated channel protein
Opens and closes
Cell indentity marker protein
Distinguishes body’s own cells from foreign cells
Cell adhesion molecule (CAM) protein
Fuses to another protein from another cell
Carrier protein
Moves substances across the plasma membrane by changing its shape
3 factors to open channels
-A chemical binding=ligand gated channel
-Electrical difference access= voltage gated channel
-mechanical deformation=mechanically gated channel
Selectively permeable
The plasma membrane allows some things to move across easily and not other things
Three types of membrane transport
Diffusion
Carrier mediated transport
Vesicular transport
Charge gradient
Inner surface of the cell is more negative and the outer surface is more positive
Chemical gradient
Concentration gradient across the cell membrane
Diffusion: shorter distance =
Faster diffusion
Diffusion: smaller substance=
Faster diffusion
Diffusion: higher temperature=
Faster diffusion
Diffusion: larger gradient =
Faster diffusion
The negative charge inside the membrane tend to favour:
The entry of cations
Diffusion: greater membrane area=
Faster diffusion
Simple diffusion
Small non polar and hydrophobic molecules can diffuse through the lipid bilayer. Large non polar molecules can get stuck in the membrane
Channel mediated diffusion
Each ion channel is specific for a particular ion
Osmosis
The movement (diffusion) of water through permeable barrier from an area of high concentration of water to a low concentration of water
Water moves through cells in two ways:
-Aquaporins; special channel proteins
-by slipping through temporary spaces between lipids caused by their movements
Tonicity
Relates to how the solution influences the shape of body cells
Isotonic
The concentrations of the solutes are the same on both sides of the membrane. Water molecules enter and exit at the same rate and cell stays a normal shape
Hypotonic
The concentrations of solutes is higher inside the cell and too much water moves into the cell.
Can cause hemolysis
Hypertonic
The concentrations of the solutes are lower inside the cell and not enough water moves in. Can cause crenation
Specificity
Each carrier protein binds and transports only certain substances
Saturation limits
The rate of substance transport is limited by the availability of carrier proteins
Regulation
The cell can control the activity of carrier proteins
Facilitated diffusion
Substances move down their concentration gradient so that no energy is required. Molecule binds to a carrier protein and alters the shape of the protein
Active transport
Energy requiring process in which carrier proteins move solutes regardless of the concentration gradient
Primary active transport
Energy from the hydrolysis of ATP changes the shape of a transport protein
The Na+/K+ pump
Maintains concentration gradients of Na+ and K+ across the membrane. 3 Na’s go out as 2 K’s go in through carrier protein.
How much of our body’s energy is spent making the sodium potassium pump run
40%
Secondary active transport
As Na+ leaks into the cell other substances can be transported into the same direction or the opposite direction (getting a free ride)
Vesicular transport
Molecules too large to be moved across membrane by passive or active transport cross in vesicles. Molecules in vesicles get pinched off and go across or through the membrane in the vesicle
Exocytosis
Movement of substances out of the cell. Vesicles are brought to the plasma membrane then fuses to the membrane releasing its cargo
Endocytosis
Movement of substances into a cell
3 types of endocytosis:
- Phagocytosis- enzymes in the cells lysosomes eat the large particles
- Pinocytosis- lysosomes drink the fluid surrounding the cell
- Receptor mediated endocytosis- cells take up specific ligands
Transcytosis
Method by which substances can cross the cell
Cytosol
Fluid portion of the cytoplasm that surrounds the organelles
Organelles
Specialized structures that have characteristic shapes and perform functions in cellular metabolism
Cytoskeleton
Network of protein filaments and cylinders. Determines cell shape, supports structure, directs movement. Composed of: microfilaments, intermediate fibers, microtubules
Ribosomes
Small granules of protein and RNA
found in the nucleoli, Cytosol, outer surfaces of rough ER and nuclear envelope.
Read coded genetic messages and assemble amino acids into proteins
Endoplasmic reticulum
System of channels enclosed by membrane
Rough ER
Parallel flattened sacs covered with ribosomes.
Produces phospholipids and proteins
Synthesizes proteins that are packaged in other organelles
Often the largest organelle
Smooth ER
Lack ribosomes
Synthesizes steroids and other lipids
Calcium storage
Detoxifies alcohol and drugs
Golgi complex
System of cisterns that synthesizes carbohydrates and puts finishing touches on protein synthesis
Lysosomes
Package of enzymes bound by a membrane
Shape: mostly round
Functions: digestion of substances
Autophagy
Digestion of cells surplus organelles
Autolysis
Cell suicide, digestion of a surplus cell by itself
Peroxisomes
Resemble lysosomes but contain different enzymes and are produced by ER
Functions: produces hydrogen peroxide
Catalase breaks down excess H2O2
neutralize free radicals= detoxify drugs alcohol and other blood toxins
Mitochondria
Organelles specialized for synthesizing ATP
Powerhouse of the cell
Cilia
Function to move fluid and material along the cells surface
Flagella
Generate forward motion (sperm cells only)
Nucleus
Has its own membrane
Has genes
Nuclear envelope
Membrane surrounding nucleus similar to plasma membrane
Genes
The cells hereditary units consisting of DNA
How many chromosomes do human somatic cells have?
46 chromosomes arranged in 23 pairs and are diploid
How many chromosomes do human reproductive cells have?
23 chromosomes and are haploid
Stem cells
Continuously divide and give rise to more daughter cells
Apoptosis
Cell suicide, enzymes kill the cell