Lecture Week 3 Flashcards
What are the functions of the plasma membrane of a cell?
- Separates intracellular from extracellular environment
- Controls movement between intracellular and extracellular environment
- Responds to the environment
- Provides structural support
What are the components of the plasma membrane of a cell?
- Phospholipid bilayer
- Cholesterol
- Membrane proteins
What are the components of Cytoplasm?
Cytosol, cytoskeleton components, organelles
What does the nuclear envelope lie between?
Nucleoplasm and cytoplasm
What does the plasma membrane of a cell lie between?
Intracellular and extracellular environments
What is glycerol + 2 fatty acids called?
Diglyceride
Hydrophilic head does or does not interact with water?
Interacts with water
Hydrophobic tails does or does not interact with water?
Does not interact with water
When a phospholipid bilayer occurs, will the hydrophilic heads and hydrophobic tails arrange themselves?
Yes
Where do the hydrophilic heads go in a phospholipid bilayer?
Outer surface
Where do the hydrophobic tails go in a phospholipid bilayer?
Interior (protected from water)
Will you find cholesterol molecules embedded in a phospholipid bilayer?
Yes
What do cholesterol molecules embedded in phospholipid bilayer do?
- Can strengthen and stiffen plasma membrane
- Decreases effective temp on cells plasma membrane
What is the order of a phospholipid bilayer when arranged? Top to bottom
Heads, tails, tails, head
What is a transmembrane protein?
Goes from top to bottom of phospholipid bilayer
What is a peripheral protein?
Only on top or bottom of phospholipid bilayer (does not extend top to bottom)
What do microfilaments do in cell structure?
Strength, support, cell movement
-support microvilli for absorption
-form terminal web for plasma membrane support
What do microtubules do in cell structure?
Strength, organelle movement
-centrioles within the centrosome distribute chromosomes during cell division
-cilia move materials over the surface of a cell (short, numerous)
-flagella allow sperm cells to swim (long, singular)
How could you describe cilia and flagella?
Hair like cellular extensions
What serves as a holding spot for microtubules?
Centrosome
What are centrioles formed from?
Microtubules
What is cilium formed by?
Microtubules
What are ribosomes?
Sites for protein synthesis
What are the two kinds of ribosomes?
Free and Fixed
What is a free ribosome?
-Produce protein for the cytosol
-Some ribosomes are single, some form chains called polyribosomes
What is a fixed ribosome?
-Produce proteins for secretion or storage
-Attached to a structure
What are membranous organelles formed from?
Phospholipid bilayers
What are the two parts of the Endoplasmic Reticulum (ER)?
Rough and Smooth
What is Rough Endoplasmic Reticulum?
Contains fixed ribosomes, main site for making proteins
What is Smooth Endoplasmic Reiculum?
Site assembling lipids
What are vesicles?
Membrane bubbles of phospholipid bilayers
What are the two kinds of vesicles?
Transport and Secretory
What is a transport vesicle?
Carry substance from one part of cell to another
What is a secretory vesicle?
Secrete substances from plasma membrane
What does the Golgi Apparatus do?
Modifies, packages, and distributes the products of the ER to where they need to go
-remember this as “shipping and handling”
What are the two kinds of storage vesicles?
Lysosomes and Peroxisomes
What do Lysosome storage vesicles do?
Store enzymes for intracellular digestion
What do Peroxisome storage vesicles do?
Contain enzymes to degrade toxins
What does mitochondria do?
Sites for cellular respiration
What is cellular respiration?
Process that allows to extract energy from nutrients in food
What is the Golgi Apparatus formed from and how does it look?
-Formed from phospholipid bilayer
-Appears flat and stacked
What is the nuclear envelope?
Double membrane that separates nucleoplasm from cytoplasm
What do nuclear pores do?
Allow particles to go between nucleoplasm and cytoplasm (and vice versa)
What makes up chromatin?
DNA and proteins
What are chromosomes?
Tightly packed chromatin fibers that form during cell division
What is the nucleolus?
A region where ribosomal subunits are being produced
What makes up nucleoplasm?
Thread like structures called chromatin
What are the two parts of a ribosome?
Small subunit and large subunit
What happens after the ribosome subunits are made in the nucleolus?
Will go through nuclear pore, large and small subunit link together in cytoplasm to form ribosome
Where are components of ribosomes made?
Nucleolus
What are passive processes in movement across the plasma membrane?
Do not require cell to spend energy to fuel process
What are the three passive processes?
Simple Diffusion, Osmosis, Facilitated Diffusion
What is Diffusion?
Movement of solute and solvent down their concentration gradients until a state of equilibrium is reached
What is simple diffusion?
When molecules are crossing phospholipid bilayer of a plasma membrane or moving through channel proteins
What are the factors that affect diffusion rate?
Solute molecular size, temperature, steepness of concentration gradient, electrical forces
What is Osmosis?
Diffusion of water across plasma membrane in response to differing solute concentrations
What is osmotic pressure?
Force exerted by water as it moves across the membrane
What is hypotonic?
osmotic pressure may cause cell to swell lysis (to break)
What is hypertonic?
leads to crenation (cell shrivels up)
What is isotonic?
Maintains normal cell shape
What is Facilitated Diffusion?
Form of carrier-mediated transport that involves diffusion of solute across plasma membrane via carrier proteins
What do active processes require?
Energy to fuel process
What are the two types of active processes?
Active transport and Vesicular Transport
What are the two types of Vesicular Transport
Endocytosis and Exocytosis
What is active transport?
Movement of solute across the plasma membrane from region of low concentration to region of high concentration via carrier proteins
What is Endocytosis?
Movement of substance across plasma membrane via formation of vesicle (brings material into cell)
Receptor mediated endocytosis?
Moves specific solutes into cytoplasm
Pinocytosis?
Moves fluid (cell drinking)
Phagocytosis?
Moves solid (cell eating)
Exocytosis?
Movement of substance across plasma membrane via fusion of a vesicle with plasma membrane (takes material out of cell)
What is a solute?
Substance that can be dissolved by solvent
What is a solvent?
Substance that dissolves solute
What is a solution?
Mixture of solvent and solute substances
What is a concentration gradient?
Range of concentrations for solute and solvent from high to low over distance
What is a selectively permeable membrane?
Some substances can cross the membrane while some substances can’t