Midterm - Cells, Tissues, Organs & Organ Systems (P.2) Flashcards
Cell membranes are composed mainly of _____________ and __________, allowing certain materials to move across them.
PHOSPHOLIPIDS; PROTEINS
What is the certain quality of the cell membrane called?
SELECTIVE PERMEABILITY
The _______________ is based on the knowledge of the cell membrane?
FLUID-MOSAIC MODEL
This region is composed mainly of PHOSPHOLIPIDS and PROTEINS, allowing certain materials to move across them.
CELL MEMBRANE
Give the SIX (6) CELL MEMBRANE FUNCTIONS!
- Regulate the movement of material
- Separate the inside of the cell from the outside
- Separate various organelles within the cell
- Provide a large surface area
- Are a site for receptors
- Separate cells from one another
In water, phospholipids spontaneously form a _________.
BILAYER
Cell membranes contain zones called ____________.
LIPID RAFTS
What is the cell membrane heavily enriched in?
CHOLESTEROL
Lipis move __________ in a membrane, but flip=-flopping across the membrane is quite rare.
(a) MOVEMENT OF PHOSPHOLIPIDS; laterally
Unsaturated ______________ tails of phospholipids have _________ that keep the molecules from packing together, enhancing membrane fluidity!
(b) MEMBRANE FLUIDITY
HYDROCARBON; KINKS
____________ reduces membrane fluidity at moderate temperatures by reducing phospholipid ___________, but at _____ temperature it hinders solidification by disrupting the regular packing of phospholipids.
(c) CHOLESTEROL WITHIN THE ANIMAL CELL MEMBRANE
CHOLESTEROL; MOVEMENT; LOW
A protein that spans the membrane may provide a ___________ channel across the membrane that is selective for a particular solute.
Other ________ proteins shuttle a substance from one side to the other by changing shape.
Some of these proteins __________ ATP as an energy source to actively pump substances across membranes.
(A) TRANSPORT
HYDROPHILIC
TRANSPORT
HYDROLYZE
A protein built into the membrane may be an enzyme with its active site exposed to substances in the adjacent solution. In some cases, several enzymes in a membrane are organized as a team that carries out sequential steps of a metabolic pathway.
ENZYMATIC ACTIVITY
A membrane protein (receptor) may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. The external messenger (signaling molecule) may cause a shape change in the protein that relays the message to the inside of the cell, usually by binding to a cytoplasmic protein.
SIGNAL TRANSDUCTION
Some glycoproteins serve as IDENTIFICATION TAGS that are specifically recognized by membrane proteins of other cells.
CELL-CELL RECOGNITION
The membrane proteins of adjacent cells may hook together in various junctions such as GAP JUNCTIONS or TIGHT JUNCTIONS.
INTERCELLULAR JOINING
Microfilaments or other elements of the cytoskeleton may be noncovalently bound to membrane proteins, a function that helps maintain cell shape and stabilizes the location of certain membrane proteins. Proteins that can bind to ECM molecules can coordinate extracellular and intracellular changes.
ATTACHMENT OF THE CYTOSKELETON AND EXTRACELLULAR MATRIX (ECM)
Some molecules use their own energy to move.
PASSIVE TRANSPORT
Molecules move from an AREA of HIGHER CONCENTRATION to an AREA of LOWER CONCENTRATION
DIFFUSION
What are the three (3) types of diffusion?
- SIMPLE DIFFUSION
- FACILITATED DIFFUSION
- OSMOSIS AND FILTRATION
Net movement of molecules or ions from a region of HIGHER CONCENTRATION to a region of LOWER CONCENTRATION.
DIFFUSION
The _________ in the ________ _______ is the driving force of diffusion.
DIFFERENCE; CONCENTRATION GRADIENT
Give the FIVE (5) Factors that affect DIFFUSION RATES:
- SIZE
- TEMPERATURE
- STEEPNESS OF THE CONCENTRATION GRADIENT
- CHARGE
- PRESSURE
The diffusion of water across a selectively permeable membrane from an area of HIGH WATER CONCENTRATION to an area of LOWER WATER CONCENTRATION.
OSMOSIS
This is a special type of diffusion, not a different method.
OSMOSIS
Net diffusion of water molecules across a selectively permeable membrane between two fluids with different water concentrations
OSMOSIS
Equivalent solute concentration; results to normal cells
ISOTONIC
Concentrated solutes outside; results to SHRIVELED cells
HYPERTONIC
Dilute solutes outside; results to SWOLLEN cells
HYPOTONIC
Arrange the events that take place during gas exchange in mammals.
- Oxygen-poor blood is carried back to the heart and pumped to the lungs.
- Oxygen-rich blood is carried to the heart and pumped to the body.
- O2 diffuses out from red blood cells into the body tissues, while CO2 diffuses into red blood cells from the body tissues.
- CO2 diffuse out from red blood cells into the alveolar spaces of the lung, while O2 diffuses into red blood cells from air in the lungs
1) CO2 diffuse out from red blood cells into the alveolar spaces of the lung, while O2 diffuses into red blood cells from air in the lungs
2) Oxygen-rich blood is carried to the heart and pumped to the body.
3) O2 diffuses out from red blood cells into the body tissues, while CO2 diffuses into red blood cells from the body tissues.
- Oxygen-poor blood is carried back to the heart and pumped to the lungs.
- Fluids flow in OPPOSITE DIRECTIONS
- Allowing for efficient transfer of HEAT, GASES, or SOLUTES between them
COUNTERCURRENT EXCHANGE
- Fluids flow in the SAME direction, causing the gradient between them to decrease rapidly, which limits the efficiency of the transfer of heat, gases, or solutes.
CONCURRENT EXCHANGE
Requires ENERFY from the cell to move substances from areas of lower concentration to areas of higher concentration.
ACTIVE TRANSPORT
Active transport requires what kind of energy?
ADENOSINE TRYPHOSPHATE (ATP)
How types of carrier proteins functions during active transport?
THREE
What are the ADDITIONAL processes that move molecules across membranes in bulk?
1) ENDOCYTOSIS
- PINOCYTOSIS
- PHAGOCYTOSIS
- RECEPTOR-MEDIATED ENDOCYTOSIS
2) EXOCYTOSIS
- Form of endocytosis where the cell engulfs extracellular fluid and dissolved substances into small vesicles, often referred to as “cell drinking.”
- It is a non-specific process, meaning the cell takes in a variety of molecules from the surrounding fluid.
PINOCYTOSIS
- Process in which a cell, typically a white blood cell, engulfs large particles, such as pathogens or debris, into a vesicle called a phagosome.
- This is a more specialized form of endocytosis that is used for defense against infections and cellular cleanup.
PHAGOCYTOSIS
- Selective form of endocytosis where specific molecules, such as hormones or nutrients, bind to receptors on the cell surface before being internalized in vesicles.
- This process ensures the cell takes in only the substances it specifically needs, often with high efficiency.
RECEPTOR-MEDIATED ENDOCYTOSIS
Process where the cell takes in substances by engulfing them in vesicles.
ENDOCYTOSIS
Process where the cell expels substances by merging vesicles with the plasma membrane.
EXOCYTOSIS
What is the meaning of LDL?
LOW DENSITY LIPOPROTEIN
How does cholesterol travel in the blood?
Cholesterol travels in the blood with LDLs.
LDL acts as _________ - molecules that specifically binds with receptor proteins
LIGANDS
Through this process, LDLs gain entrance to the cell?
ENDOCYTOSIS
A condition where LDLs are FEW or MISSING thus a build up of cholesterol results in the build up of cholesterol in the blood causing early____________.
HYPERCHOLESTEROLEMIA; ATHEROSCLEROSIS
Means by which _________, ___________ and __________ are secreted in animal cells.
EXOCYTOSIS; HORMONES; NUEROTRANSMITTERS; DIGESTIVE ENZYMES
Emotional teras have protein-based hormones called?
LEUCINE ENKEPHALIN
A natural painkiller that is released when stressed.
LEUCINE ENKEPHALIN
