UNIT 2: Cellular Level of Organization Flashcards
_______ are the most basic structural and functional units of all living things.
Cells
Cells are made up primarily of the same WHAT four (4) elements?
**Tip: CHON
Carbon
Hydrogen
Oxygen
Nitrogen
**CHON
What are the nine (9) cellular functions?
Tip: SED2M2C2R
- Differentiation
- Movement
- Conductivity
- Metabolic Absorption
- Secretion
- Excretion
- Respiration
- Reproduction
- Communication
**SED2M2C2R
- CELLULAR FUNCTIONS -
Unspecialized cells, like stem cells, become specialized through “maturation”; they also acquire specialized functions.
Differentiation
- CELLULAR FUNCTIONS -
A necessary function in living organisms that enables them to grow, divide, and migrate to areas where they are needed.
Movement
- CELLULAR FUNCTIONS -
Chief function of nerve cells and cardiac cells. They respond to stimuli by generating nerve impulses that are connected to other cells.
Conductivity
- CELLULAR FUNCTIONS -
All cells take in and use nutrients and other substances from their surroundings.
Metabolic Absorption
- CELLULAR FUNCTIONS -
Involves the regulated release of intracellular products from cells.
Secretion
- CELLULAR FUNCTIONS -
Process by which cells get rid of waste products or metabolic wastes.
Excretion
- CELLULAR FUNCTIONS -
Cellular process by which cells produce Adenosine Triphosphate (ATP) through the absorption of oxygen.
Respiration
- CELLULAR FUNCTIONS -
Tissue growth occurs as cells enlarge and reproduce themselves. This also includes the production of new cells in order to replace cells lost through “apoptosis” (programmed cell death).
Apoptosis happens when cells detect molecular or metabolic errors within themselves; it helps prevent the propagation of cells that may cause cancer,
Reproduction
- CELLULAR FUNCTIONS -
Cells communicate with each other; critical for all other cellular functions to work, Maintains dynamic steady state.
Communication
What cellular function is when:
Nerve cells mature from stem cells and acquire the function of being conductive so that they can respond to stimuli through action potentials
Differentiation
What cellular function is when:
Muscle cells generate forces that produce motion; skeletal muscles produce limb movement and smooth muscles in blood vessels regulate blood flow through vasodilation and vasoconstriction.
Movement
What cellular function is when:
Neurons are able to transmit signals from one neuron to other neurons or muscles and glands in order to elicit a response to detected stimuli.
Conductivity
What cellular function is when:
Cells in the intestines and kidneys are specialized in carrying out absorption and reabsorption.
Metabolic Absorption
What cellular function is when:
Mucus gland cells can synthesize new substances, which they secrete as needed.
Secretion
What cellular function is when:
Degradation of wastes by lysosomes prior to their excretion.
Excretion
What cellular function is when:
Cellular respiration, which occurs in the mitochondria (hence, mitochondria is known as the powerhouse of the cell).
Respiration
What cellular function is when:
When organisms grow, it isn’t because cells are getting larger. Organisms grow because cells are dividing to produce more and more cells
Reproduction
What cellular function is when:
Synaptic signaling, which allows signaling or communication between two neurons.
Communication
- PARTS OF THE CELL -
A cell is divided into three (3) main parts:
- Plasma/Cell Membrane
- Cytoplasm (cytosol and organelles embedded)
- Nucleus
- PARTS OF THE CELL -
Regulates transport of materials entering and exiting the cell.
Plasma membrane
- PARTS OF THE CELL -
The _______ ________ is a flexible barrier that surrounds the cytoplasm of the cell.
Plasma membrane
- PARTS OF THE CELL -
This is the “basic framework of the plasma membrane”.
Made up of three (3) types of lipid molecules. What are these?
Lipid bilayer
- Phospholipids
- Cholesterol
- Glycolipids
- PARTS OF THE CELL: Lipid Bilayer -
Comprise 75% of lipids in the plasma membrane
Each molecule is “amphipathic”, meaning it has both polar and nonpolar regions.
—> Polar region (heads): Hydrophilic; faces both surfaces
—> Nonpolar region (tails): Hydrophobic; line up toeach other in the interior.
Phospholipids
- PARTS OF THE CELL: Lipid Bilayer -
Comprise 20% of the lipids
Weakly amphipathic and interspersed among other lipids in both layers.
Has steroid rings and hydrocarbon tails that are nonpolar and hide in the middle of the cell membrane.
Cholesterol
- PARTS OF THE CELL: Lipid Bilayer -
Comprise 5% of the lipids.
They have a “carbohydrate” that forms a polar head only on the side of the membrane facing the extracellular fluid.
Glycolipids
- PARTS OF THE CELL: Membrane Proteins -
Divided into two (2). What are these and briefly explain each.
1) Integral proteins: Extend into the entire lipid bilayer among the fatty acid tails of the phospholipid molecules
2) Peripheral proteins: Found at the inner/outer surface of the membrane and can be stripped away without disturbing the membrane integrity.
- FUNCTION OF THE MEMBRANE PROTEINS -
Membrane proteins become passageways that allows specific substances to pass through.
Formation of channels
- FUNCTION OF THE MEMBRANE PROTEINS -
Bind to specific substances, change shape, and move the substance across the plasma membrane.
The process is called “transporter-mediated diffusion”
Transporter proteins
- FUNCTION OF THE MEMBRANE PROTEINS -
Acts as “cellular recognition sites” which bind to specific substances (usually a hormone, neurotransmitter, cytokine, growth factors, etc.)
Receptor proteins
- FUNCTION OF THE MEMBRANE PROTEINS -
Allow cells to recognize other similar cells (e.g. the Major Histocompatibility Complex)
“Allow for the recognition of “self” from “non-self” to enable the immune system to attach foreign antigens and not self-antigens.
Cell Identity Markers
- FUNCTION OF THE MEMBRANE PROTEINS -
Anchor proteins in the cell to other cells.
Allow cell movement and maintain the shape and structure of cells.
Linkers
- FUNCTION OF THE MEMBRANE PROTEINS -
Speeds up the cellular reactions.
Enzymes
- TRANSPORT ACROSS THE PLASMA MEMBRANE -
Difference in the concentration of a chemical between one side of the plasma membrane and the other.
- Example: Oxygen and sodium are more concentrated OUTSIDE the cell with carbon dioxide and potassium ions more concentrated INSIDE the cell.
Concentration Gradient
- TRANSPORT ACROSS THE PLASMA MEMBRANE -
Difference in the charges between the surfaces inside and outside the membrane.
- Example: The INNER surface of the membrane is more NEGATIVELY CHARGED whereas the OUTER surface is positively charged
**This is important as it provides power to operate cell membrane functions.
Electrical Gradient
- TRANSPORT ACROSS THE PLASMA MEMBRANE -
Type of transport the DOES NOT REQUIRE ENERGY and usually moves across a concentration gradient.
Has three (3) types. What are these?
Passive Transport
- Diffusion
- Facilitated Diffusion
- Osmosis
- TYPE OF PASSIVE TRANSPORT -
Substance moves across the lipid bilayer of the plasma membrane without the help of membrane transport protein
Diffusion (higher to lower)
- TYPE OF PASSIVE TRANSPORT -
Substance moves across the lipid bilayer aided by a channel protein or carrier protein.
Facilitated diffusion
- TYPE OF PASSIVE TRANSPORT -
Movement of water from lower to higher solute concentration and penetrate the membrane by diffusion through the lipid bilayer or through “aquaporins,” transmembrane proteins that function as water channels.
Osmosis (lower –> higher)
- OSMOSIS -
What is tonicity? What are its three (3) types and explain each.
Measure of the solution’s ability to change the volume of cells by altering their water concentration.
- Isotonic solution
- Hypotonic solution
- Hypertonic solution
- TYPES OF SOLUTION BASED ON TONICITY -
- Equal solute concentration
- Net movement of water us zero (0)
- Cell maintains its shape
Isotonic solution
- TYPES OF SOLUTION BASED ON TONICITY -
- Amount of solute concentration outside is less
- Movement is INTO the cell
- Causes “swelling” and hemolysis (bursting)
Hypotonic solution
- TYPES OF SOLUTION BASED ON TONICITY -
- Amount of solute concentration outside is more
- Movement is OUTSIDE the cell
- Causes crenation or “shrinking”
Hypertonic solution
- ACTIVE TRANSPORT -
Describe how the active transport works.
An energy-requiring process that moves solutes (ions, amino acids, etc.) and monosaccharides against a concentration gradient.
- ACTIVE TRANSPORT -
The most prevalent primary active transport mechanism is the __________?
Sodium ion/potassium ion pump
(PISO: potassium /K+/ in, sodium /Na+/ out)
**Requires 40% of cellular ATP and all cells have this pump.
- TRANSPORT IN VESICLES -
A vesicle is a small membranous sac formed by budding off from the existing membrane.
What are its two (2) types?
- Endocytosis
- Exocytosis
- TYPE OF VESICLE TRANSPORT -
Bring something into the cell. Has two (2) types, what are these?
Endocytosis
- Phagocytosis
- Pinocytosis
- TWO TYPES OF ENDOCYTOSIS -
Cellular eating; cells “eat” solid substances.
Usually carried out by macrophages and WBCs.
Phagocytosis
- TWO TYPES OF ENDOCYTOSIS -
Cellular drinking; cells “drink” liquid substances.
No receptor proteins are involved.
Pinocytosis
- TRANSPORT IN VESICLES -
Releasing something from the cell.
Process by which substances (digestive enzymes, hormones, neurotransmitters, or waste products) are released by the cells.)
Exocytosis
- CYTOPLASM -
The cytoplasm has two components: _______ and ________.
cytosol
organelles
- CYTOPLASM -
- This is the intracellular fluid
- The medium in which many metabolic reactions occur.
- 55% of the total cell volume
Cytosol