Chapter 2 - Biochemistry Flashcards
Types of Transport
Passive, Active, Bulk Membrane
Passive Types
- simple diffusion
- osmosis
- facilitated diffusion
Passive Transport
- Moves substances across the membrane along a concentration gradient (from an area of high concentration to an area of low concentration)
- Tends to involve smaller molecules (H2O, CO2, O2)
- Requires no cellular energy
Diffusion
is the net movement of a substance from a region of higher concentration to a region of lower concentration
Osmosis
the diffusion of water molecules across a semipermeable membrane
Isotonic
When the concentration of the ICF and ECF are equal
Hypotonic
- When the concentration of the ICF is higher than the ECF (more water in ECF than ICF)
- Water molecules move into cell and cell gets bigger and could burst (lysis)
Hypertonic
- When the concentration of the ECF is higher than the ICF (more water in ICF than ECF)
- Water molecules move out of cell and cell may shrivel (plasmolysis)
Facilitated Diffusion
- the transport of ions and polar molecules through a membrane via special proteins
- For those molecules that cant diffuse or are not diffusing quickly enough (e.g. ions, water, amino acids, sugars etc.)
Membrane Proteins
Channel Proteins, Carrier Proteins
Channel Proteins
Channel proteins form hydrophilic pathways through which water and certain ions can pass through
Carrier Proteins
Carrier proteins binds to a specific molecule and transports it across the lipid bilayer
Active Types
Primary Active Transport, Secondary Active Transport
Primary Active Transport
- Active transport is the movement of substances against the concentration gradient
- Primary active pumps move positively charged ions (H+, Ca2+, Na+, and K+) across
membranes using ATP
Active Transport - Secondary
- A secondary active transport pump uses the concentration gradient of an ion, established by a primary pump for its energy source
- Example: sodium-potassium pump
Bulk Membrane Types
Endocytosis, Exocytosis
Endocytosis
when the cell membrane folds inward and forms a vesicle to capture materials from the ECF
Endocytosis Types
- Pinocytosis
- Receptor-Mediated Endocytosis
- Phagocytosis
Pinocytosis
extracellular water is taken in along with any molecules that happen to be in the water (aka ‘cell drinking’)
Receptor-Mediated Endocytosis
molecules to be taken in are bound to the outer cell surface by raptor proteins
Phagocytosis
cells engulf bacteria, parts of dead cells, viruses or other foreign particles (aka ‘cell eating’)
Exocytosis
- secretory vesicles from inside the cell attach to the cell membrane and release contents to ECF
- Example: carbohydrates needed to make cell wall (cellulose) exported out of the cell this way
Transport Functions
- Take in nutrients
- Expel waste
- Communicate with the environment
- Communicate with neighboring cells
Nucleus
Protects and controls access to the DNA; makes ribosome subunits
Rough ER
Produce proteins for the rest of the cell
Smooth ER
Helps synthesize and concentrate various substances needed by the cell
Golgi Body
Modifies new polypeptide chains; sorts and ships proteins and lipids
Transport/Secondary Vesicle
Transports substances within a cell and or releases them from the cell
Mitochondrion
Generates ATP and other molecules
Chloroplast
Produces sugars using light energy, carbon dioxide, and water
Lysosome
Carries out intracellular digestion
Peroxisome
Inactivates toxins
Vacuole
Provides storage and contains waste; in plants, maintains cell size and shape
Ribosome
Assembles polypeptide chains that are used to form proteins
Centriole
Makes microtubules for the cytoskeleton; involved in cell division
Plasma Membrane
Separates the interior of the cell from the outside environment
Theory of Endosybiosis
Suggests that the organelles arose from prokaryotes (mitochondria)
Cytoskeleton
Provides structure that helps maintain their shape and organization
Microtubules
Helps support the shape of a cell
Microfilaments
Generates the forces used in cellular contraction and basic cell movements
Nuclear Envelope
Membrane barrier that separates the nucleus from the cytoplasm in eukaryotic cells
Cytosol
- Provides structural support to the cells and organelles and acts as a plat form for the transport of molecules across the cell
- Fluid part of cytoplasm
Nucleoplasm
Liquid that contains nucleus
Nucleolus
Produce and assemble ribosomes
Cell Wall
the outer covering of a plant cell
Organelle
An internal functional structure that is located within the cytosol of a cell
