Chapter 4-5 Test Flashcards
Eukaryote
Has nucleus & membrane bound organelles
Prokaryote
Has no nucleus, no membrane bound organelles
What organelles do prokaryotes have?
- a cell wall made of protein
- a plasma membrane made of phospholipids and protein
- ribosomes that synthesize proteins; made of protein and RNA
Biological Membranes include…
- Nucleus, Mitochondria, Golgi
- Composed of phospholipids and proteins
- Transmembrane proteins live here!
Trans-Membrane Proteins
- Live in biological membrane
- may have carbohydrates which are sticky side chains
For a protein to be found in a biological membrane, it most likely contains…
many amino acids
Eukaryote
- Plasma Membrane that surrounds the cell separating the inside from the outside and regulates flow
4 Major Structures of the Nucleus
- Nucleolus; synthesis
- Nuclear Envelope; double bilayer, has nuclear pores
- Nuclear Pore; made of proteins, transfer RNA
- Chromatin; combo of DNA & Proteins
A cell contains a large # of ribosomes… it may be specialized for synthesizing _____
proteins
Prokaryotes don’t have this organelle.
Endoplasmic Reticulum
Ribosomes
- Synthesize proteins
- Found in cytoplasm (free ribosomes - synthesize soluble proteins) & the Rough ER (synthesize insoluble trans-membrane proteins or can secrete proteins)
Smooth ER
- Synthesize lipids
- Carbohydrate breakdown
- Calcium secretion / storage
Golgi Apparatus:
- Protein modification (can make glycoproteins with sugar)
- Polysaccharide synthesis
- 2 sides:
1. Receiving Side: Cis
2. Output Side: Trans
Lysosomes
(not found in plants)
- Digests macromolecules (polysaccharides, fats, nucleic acids)
- Filled with digestive enzymes
Autophagy
Lysosomes break down a damaged organelle
Phagocytosis
Lysosomes digest food
Why is phagocytosis required for food particles to enter a cell?
Food particles are generally water soluble and cannot pass through a biological membrane
Central Vacuole
(found in plants)
- stores water and some nutrients
Endomembrane System
the ER is connected to nucleus
- Nucleus, ER, Golgi, Lysosome
Mitochondrion
- Parts: Outer membrane, inner membrane, intermembrane space, cristae, matrix
- the site of cellular respiration
- has its own DNA and Ribosomes
- can divide on own
Proteins of the extracellular matrix are produced by ribosomes in which part of the cell?
Rough ER
Peroxisomes
- Lipid catabolism, dehydrogenation (removing H groups and fats) and H2O2 formation
Mitochondria
- Carries out respiration
- has circularized DNA
- Pyruvate breakdown
Photosynthesis is carried out by _______
Chloroplasts
Embosymbiont theory
Cells has an endomembrane system and takes the nutrients they need from their surroundings
Cytoskeleton
Includes (3)
- Microtubules
- Int Filaments
- Microfilaments
Microtubules
(25 um)
Support movement within cell
Made of tubulents
Motility of Kinesin: a walking protein across microtubules
Int Filaments
(12 um)
Made of keratin
Anchorage and Support
Micro Filaments
(7 um)
Support Cilia
Muscle Contraction
Movement of cell contents and formation of psudopodia
Glycoproteins
Proteoglycan, Collagen, Fibronectin
Proteoglycan
Cell communication
Made of carbohydrate and a core protein
Collagen
most abundant protein (40%)
makes connective tissue
short chained carbohydrates
Integrins
Cell signalling to regulate cell division
Cellular Junctions
- Tight… prevent water from seeping in
- Desosomes… proteins that hold cells together
- Gap… neurons communicate
Fluid Mosaic Model
trans-membrane proteins embedded in phospholipid bilayer are important to function of cell
Can proteins connected to cytoskeleton move?
No
Trans Membrane Proteins
proteins that go across a membrane. have hydrophobic side chain amino acids has N terminus, alpha helix, c terminus Functions: (6) - Transport - Enzyme Activity - Cytoskeleton and ECM - Cell-Cell Recognize - Intercellular join - signal transduction
What must be true about drug patches solution being absorbed effectively?
The solution must be hydrophobic
Diffusion
passive transport. Movement of particles from H to L concentration to reach equilibrium
Albert Einstein discovered this.
Osmosis
Water only. Diffuses water to reach equilibrium
Water solute ratio must be equal
This is how plants stand up straight
H to L concentration
Isotonic
Same concentration inside and outside
P: Flacid
A: Normal
Hypotonic
Less solution in cell… more solution outside.
P: Normal (turgid)
A: Lysed (burst)
Hypertonic
More solution in cell… less solution outside
P: Plasmolyzed
A: Shrivel
If celery is immersed in fresh water, its stiff but in salt water its limpy. This means the fresh water is _____ and the salt water is ____
Hypotonic, hypertonic
Facillitated Diffusion
2 types:
- Channel Proteins
- Carrier Proteins
- Gases readily go through membranes, but hydrophillic and charged ions need help
- Simple Diffusion: needs no help
- ion channels can open and close
Na / K ATPase pump
3 NA out, 2 K in. relatively negative charge inside
What property of Na/K ATPase moves K+ from outside of cell to inside?
When active sites are open towards inside, affinity for K+ is lower
Electrogenic Pump:
goes against concentration gradient. (from L to H) and produces membrane potential.
Co-Transport
uses multiple pumps and uses concentration gradients of one pump to the other. DOES NOT directly use ATP
ex: Sucrose
Why is the sucrose co transport not an active transport mechanism?
It doesnt use energy from ATP
Endocytosis (3 types)
Phagocytosis: pseudopods EATS particle of food forming food vacuole!
Pinocytosis: brings lots of little things in the cell.. regular occurance
Receptor Mediated Endocytosis: triggered when signaling molecules bind to receptors on plasma membrane
Signaling (think of phone calls)
Local: Paracrine, Synaptic
Long Distance: Endocrine Hormonal…. anything hormonal
Paracrine
has target cells that secret regulators through secretory vesicles to other target cells
Synaptic
Signaling molecules bind to receptor
ligame = signaling molecule
Endocrine Hormonal
uses circulatory system to transport hormones across body
Insulin is an endocrine hormone. It exerts its affects by
transport through circulatory system
Basic Steps in Extra/Intracellular cell signaling
- Earl Sutherland
1. Reception - Ligame binds to receptor which changes shape of receptor (activated = change shape)
2. Transduction - Signal transduced to intracellular signals. Cascade molecules, chain reaction
3. Response - activation (change shape) of some cellular response
2 FEATURES:
- Amplification
- Regulation
When a receptor is activated, we mean that ___
the SHAPE HAS CHANGED!! :D
G Protein
an enzyme that breaks down GTP to make GDP… and also it can bind GTP. (GTP is like ATP but instead of adenosine, it is guanine)
G Protein Coupled Receptor
a receptor coupled with G protein. Activated receptor can bind G protein if the receptor has GTP.
GTP will not stay bound to an enzyme
When a receptor is activated, how many G Proteins can be activated?
Many! as long as ligamand is attached
What stops G Protein from being activated?
When the ligand dissaccosiates from the receptor
Ligand Gated Channel
- Most common type in nervous system
- Ion channels in membrane that open or close when a ligand binds. When ligand leaves, gate closes.
2 POTENTIAL CELL RESPONCES:
- (+) or (-) … aka membrane potential
- Calcium = signaling ion… lets in calcium
Steroids Mediate what?
Cell signaling.
Steroids in cytoplasm. Can cross plasma membrane on own. Binds to receptor in cytoplasm then goes to nucleus where mRNA alters gene. Once left, it makes protein.
Cell response= transcription
Phosphorylation Cascade
a series of enzyme (kinase) that grabs phosphate to stick to another kinase
- Amplification and Regulation
- Dephosphorylate proteins
How might phosphate activity affect a phospholation cascade if it increase?
Might reduce cellular response.
Are inverse. Phosphate activity decreases when the cascade increases and inversley the same.
Second Messenger Cascade
Not protein.
Includes Calcium
- Adenylyl Cyclase when activated takes ATP molecule and converts it into cAMP—> protein kinase—-> cellular response
Which can regulate gene expression
Steroid transcription factors
Protein Kinase
A protein kinase is a kinase enzyme that modifies other proteins by chemically adding phosphate groups to them
