Module 3- Midterm- Cells Flashcards
Golgi Apparatus Discription
-packaging proteins from rough ER into membrane-bound vesicles
produce 2 different types of vesicles:
-secretory vesicles (transport proteins to
extracellular environment)
-storage vesicles (lysosome, where contents are
stored within the cell)
Free Ribosomes Description
- dense granules of protein and RNA
- manufacture proteins from amino acids under control of cells DNA
- form in groups of 10-20, called polyribosomes
Mitochondrion Description
- where most ATP is generated
- number of mitochondria in each cell depends on demand of energy
- can replicate itself without cell division (during times of increased demand, like working out)
Endoplasmic Reticulum Description
- site for synthesis, storage, transport of lipid and protein molecules
- proteins manufactured are packaged into vesicles and sent to Golgi
- rough ER= proteins
- smooth ER= lipids
Cell Membrane Description
- role in detecting chemical signals from other cells
- forms links with adjacent cells
- regulate passage of substances
Centriole Description
-bundles of microtubules responsible for directing DNA movement during cell division
Nucleolus Description
-contains DNA that produces RNA found in ribosomes
Phospholipids and the Cell Membrane
- phosphate head
- fatty acid tail
- lipid bilayer: heads face toward water
- barrier to water and water-soluble substances such as: ions, sugar, urea
- oxygen, carbon dioxide and steroid hormones pass easily
Membrane Protein Responsibilities
- receptors for chemical attachment of hormones and neurotransmitter
- enzymes that help chemical reactions or breakdown molecules
- Ion channel or pore for water-soluble substances
- Membrane transport carriers
- Cell-identity markers, antigens or glycoproteins
Membrane Transport Mechanisms
- Endo/exocytosis
- Diffusion through the lipid bilayer
- Diffusion through a protein channel
- Facilitated diffusion
- Active transport
What is diffusion?
- movement of substance from high concentration to low
- substance continues to move until net zero/equilibrium ( substance still moves)
Electrical Gradient- Diffusion
- electrically charged molecules tend to move toward areas of the opposite charge
- positive move to negative, down their gradient
Electrochemical Equilibrium
- if chemical and electrical gradients are in opposite directions, the ion movement will depend on the balance of the two gradients
- will stop moving when molecules reach electrochemical equilibrium (equal and opposite in direction)
Diffusion of Lipid Soluble Substances
- oxygen, carbon dioxide, and steroid hormones
- can diffuse right through
Diffusion Factors
- Size of protein channels (sugar too large)
- Charge on molecule (like charges repel)
- Electrochemical gradient
- Number of channels in the membrane
Facilitated Diffusion
- substances that cannot pass or are too large for channels can still pass through fast
- molecules attach to protein carriers on membrane and cause change in shape in the protein
- after protein changes shape, which opens a protein channel or the protein rotates the molecule to the inner surface of the membrane where it is released
How does Simple diffusion and Facilited diffusion differ?
- rate of transport is determined by amount of available proteins
- once all carriers are saturated, the system cannot operate any quicker
- the speed at which the carriers change shape is limited
- shows chemical specificity
- may be competitively inhibited
What is chemical specifity?
-a given carrier protein will only interact with a specifically shaped molecule
What is competitive inhibition?
-may be inhibited by molecules that are very similar in shape
Active Transport
- requires protein carriers that span the cell membrane
- can be saturated, shows chemical specificity, competitive inhibition
- Requires ATP
- moves molecules from low to high conc’
- example of this is sodium potassium pump
What is osmosis?
- requires special pores
- the amount of water that diffuses out, diffuses in
- in certain conditions, there can be a concentration difference of water across the membrane, when this happens there is a net movement of water, down the concentration gradient
- pure water has a high concentration in water and a low concentration in solute
- a solution that has a high concentration in solute, has a low concentration in water
what is a solute?
-substance that is being dissolved into a liquid
what is a solvent?
- is the liquid that is doing the dissolving
- generally water
what is a solution?
- is what you get when you dissolve a solute in a solvent
- the final product
