Module 3 (Cells and Membranes) Flashcards
Aquaporins
Channel proteins that facilitate the passage of water
Influx
Movement of a substance into a cell
Efflux
Movement of a substance out of a cell
Diffusion
Spontaneous
Net movement from high concentration to low concentration
Passive Transport
Requires no energy to move molecules across a membrane
Simple Diffusion
Movement of small molecules or hydrophobic molecules through the cell membrane
Facilitated Diffusion
Molecules that move across a concentration gradient, but through a protein transporter
Channel Protein
Formed by integral membrane proteins
Selectively permeable
Sometimes exist as gated channels
Carrier proteins
Specific molecules bind to transporter and moves across concentration gradient
How does a carrier protein work?
A molecule binds to the carrier protein, and it triggers a structural change in the protein. The protein is now exposed to the other membrane surface, and diffuses across concentration gradient.
What type of membrane protein has a transmembrane segment?
Integral
Osmosis
The diffusion of water across a semi-permeable membrane
Tonicity
The ability of a surrounding solution to cause a cell to gain or lose water
Osmotic Pressure
the external pressure that must be applied to stop osmosis
Crenation
Animal cells shrivel and die when hypertonic
Plasmolysis
Plant cells will pull away from surround cell wall
Hypotonic
Solution has a lower [solute] than the cell, water moves into cell, cell can burst
Hypertonic
Solution has higher [solute] than the cell, water leaves cell
Hemolysis
Red blood cells swell and eventually burst
Turgor Pressure
The pressure from plant cells pushing against their surrounding cell wall
Active Transport
Movement of substances against the concentration gradient, requires energy
Isotonic
When the [solute] is equal both inside and outside the cell
Primary Active Transport
Active transport that directly breaks down ATP to move solutes against a concentration gradient. Usually uses a transporter
Protein carrier
Active transporter
Electrochemical Gradient
Has both an electrical (charge) component and a chemical component. Can drive the movement of other molecules through secondary active transport
Secondary Active Transport
Uses an electrochemical gradient to move ions across the membrane
Antiport
A membrane transport process that carries one substance in one direction and another in the opposite direction.
Symport
A membrane transport process that carries two substances in the same direction across the membrane.
Endoplasmic Reticulum
Synthesis of proteins and lipids, network of tubules and flattened sacs
Lumen
The interior space of the endoplasmic reticulum
Rough Endoplasmic Reticulum
Has ribosomes, makes proteins
Smooth Endoplasmic Reticulum
No ribosomes
Fatty acid and phospholipid synthesis
Ribosomes
Sites of protein synthesis
May also be found free in the cytosol
Golgi Apparatus
Modifies and sorts proteins and lipids produced by the ER, also adds carbohydrates to proteins and lipids (glycolipids and glycoproteins)
Cisternae
Flattened sacs in the golgi apparatus, surrounded by small vesicles
Glycosylation
Where sugars are covalently linked to lipids or specific amino acids of proteins
Mitochondria
Specialized organelles that harness energy for the cell. They grow and multiply independently and contain their own circular genomes.
Cytoskeleton
A protein scaffold that provides the cell structure
Cell wall
In plant cells, provides additional support to the cell
Vacuoles
Contribute to the structure of a plant cell by maintaining turgor pressure
Chloroplasts
Convert the energy from sunlight into chemical energy
The Endomembrane System
The system of interconnected organelles within the cell
Bulk Transport
Cells bring in and remove larger molecules and particles across the membrane, without breaking continuity of the cell membrane
Exocytosis
A vesicle fuses with the cell membrane and releases contents into the extracellular space
Endocytosis
The process where material from outside the cell is brought into a vesicle that can fuse with other organelles, and bring it inside.
Invaginates
Forms a pocket around the target material
Phagocytosis
(Cell eating) Uptake of particulate matter and delivery to a lysosome via a phagosome
Phagosome
Intracellular vesicle containing material taken up by phagocytosis.
Phagocytosis provides…
Nutrition and defense
Pinocytosis
(Cell drinking) A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.
Receptor-mediated endocytosis
Material binds to receptor proteins on cell membrane, vesicle forms around it and delivers material to endosomes
Endosomes
Transport, package, and sort cell material traveling to and from the membrane
Early endosomes
Located near peripheral region of cell.
Late endosomes
Located in interior part of the cell, and receive material from early endosomes and Golgi apparatus
Clathrin
Protein that coats the inward-facing surface of the plasma membrane and assists in the formation of specialized structures, like coated pits, for receptor-mediated endocytosis
Nuclear Envelope
A double membrane that surrounds the nucleus of a cell
Nuclear pores
Allow molecules to move into and out of the nucleus, found on the nuclear membrane
Lysosomes
Specialized vesicles derived from the Golgi apparatus, they degrade damaged or unneeded macromolecules (proteins, nucleic acids, lipids, and complex carbohydrates). Contain enzymes that allow them to break down material.
What is the pH of a lysosome?
Around 5, which is moderated by a proton pump
Outer membrane of mitochondria
Contain integral proteins, that form large, nonselective membrane channels called porins
Intermembrane space of mitochondria
An aqueous compartment between outer and inner membrane
Inner membrane of mitochondria
Highly convoluted, and is the location for the electron transport chain and ATP synthase
Mitochondrial matrix
The location of the citric acid cycle, ribosomes and DNA
What is the function of a chloroplast?
To be the location where photosynthesis takes place
Photosynthesis
Taking the sun’s energy and converting it into simple sugars
Thylakoid membrane
Contains light-collecting molecules called pigments (eg. chlorophyll)
Found in chloroplasts, is inner membrane
Thylakoids
Flattened membrane sacs within chloroplast
Lumen (chloroplast)
Space inside a thylakoid
Grana
The orderly stacks of thylakoids in a chloroplast
Stroma
Space surrounding thylakoids
Cyanobacteria
What do chloroplasts resemble?
Where do chloroplasts originate?
Proteobacteria
What do mitochondria resemble?
Where did mitochondria originate?