Chapter 6

Question 1

Functions of biological membrane

Answer 1

Separates the internal environment of the cell organelles from its external environment
Selective permeability
Compartmentalization

Question 2

What is the general structure of the biological membrane?

Answer 2

Fluid mosaic model

Question 3

Fluid

Answer 3

Lipids and proteins can move relative to each other within the membrane

Question 4

Mosaic

Answer 4

Made up of individuals components (lipids, proteins, and carbohydrates)

Question 5

What do the phospholipids do in the biological membrane?

Answer 5

Form the basic framework of a membrane

Question 6

What do proteins do in the biological membrane

Answer 6

Embedded in the membrane or loosely attached to its surface (carry out key functions)

Question 7

What do carbohydrates do in the biological membrane structure?

Answer 7

May be attached to membrane lipids and proteins (carry out key functions)

Question 8

Membranes of specific cells and organelles differ

Answer 8

In the kinds of proteins and lipids they contain

Question 9

Major groups of membrane proteins

Answer 9

Integral and peripheral

Question 10

Integral

Answer 10

Penetrate the hydrophobic interior of the lipid bilayer, some extend across the lipid bilayer, other are only partially embedded

Question 11

Peripheral

Answer 11

Not embedded in the lipid bilayer at all; loosely bound to the surface of the membrane

Question 12

Major functions of membrane proteins

Answer 12

Transport
Enzymatic activity
Signal transduction
Recognition
Intercellular joining

Question 13

What do plasma membrane adhere to

Answer 13

The extracellular matrix

Question 14

Integrin

Answer 14

The transmembrane protein

Question 15

What do integrin do?

Answer 15

The binding to the matrix outside of epithelial cells and to act in filaments inside the cells

Question 16

Integrin binding is

Answer 16

Non covalent and reversible

Question 17

Why is integrins this important?

Answer 17

This allows cell to move within the tissue by the binding and reattaching of integrin to the extracelluar matrix

Question 18

When integrin no longer mediate this attachment

Answer 18

Cell separate from the matrix structure - cancer cells

Question 19

Glycolipids

Answer 19

Carbohydrates + lipid - facilitate cell recognition (self vs. non self)

Question 20

Glycoprotein

Answer 20

Carbohydrates + protein - serve as receptors for chemical signals (communicate with one another)

Question 21

Major functions of membrane carbohydrates

Answer 21

Cell to cell recognition

Question 22

Fluidity of biological membranes

Answer 22

Allows to membrane to be able to move and change chape

Question 23

Membrane fluidity

Answer 23

Must remain stable within the movement

Question 24

What is the result of increased fluidity

Answer 24

Membranes can’t hold its shape, or support protein function

Question 25

What is the result of decrease fluidity

Answer 25

Permeability changes, enzymatic proteins are affects

Question 26

Factors the influence fluidity

Answer 26

Temperature and cholesterol

Question 27

What is the result of low temperature for fluidity

Answer 27

Fluidity decrease, energy decreased = decreased movement so phospholipids are tightly packed

Question 28

What is the result of high temperature on fluidity

Answer 28

Fluidity increase, increase energy = increased movement, so phospholipids move farther apart

Question 29

Cholesterol

Answer 29

Acts as a buffer to maintain stability

Question 30

What does cholesterol at low temps do?

Answer 30

Fluidity increase: cholesterol between phospholipid increase distance between them

Question 31

How does cholesterol at high temps effects fluidity

Answer 31

Fluidity decrease : cholesterol between phospholipid increases number of molecules in the space

Question 32

Selective permeability

Answer 32

A property of boiological membrane that allow them to regulate the passage of substance across them

Question 33

What molecules can cross the lipid bilayer easily without?

Answer 33

Non polar molecules

Question 34

What molecule need assistance from transport proteins

Answer 34

Polar molecules and ions

Question 35

Why is the membrane permeability so crucial?

Answer 35

It’s certain molecules or ions pass through a lipid bilayer more or less readily or rapidly than other, the homeostasis of an organelle or cell can be compromised.

Question 36

A membrane permeable and impermeable to what?

Answer 36

Permeable to solutes that can easily cross it Impermeable to those who cannot

Question 37

Passive transport

Answer 37

Energy for the passive transport comes from the concentration gradient: no energy INPUT is required

Question 38

What are the two types of passive transport?

Answer 38

Simple diffusion and facilitated diffusion

Question 39

Facilitated diffusion

Answer 39

Required no INPUT of energy Substance diffuse according to their concentration gradient Aided my transport proteins

Question 40

What are the types of transport proteins

Answer 40

Channel proteins and carrier proteins

Question 41

Channel proteins and types?

Answer 41

Transmembrane proteins that form a tunnel Ion channels- allow ions to diffuse across the membrane; most are gated to can be closed and opened Aquaporins - allow water to pass through the membrane during osmosis

Question 42

Carrier proteins

Answer 42

Membrane proteins that bind substances and speed their diffusion through the bilayer - polar substances, sugars, amino acids

Question 43

Active transport

Answer 43

Energy dependent transport of a substance across a biological membrane against the concentration gradient. This required and energy source often adenosine triphosphate

Question 44

What happened when a macromolecule is too large to cross the membrane

Answer 44

They can be taken in my endocytosis or secreted by membrane vesicles

Question 45

Endocytosis

Answer 45

Bring molecules and cells into a eukaryotic cell, the cell membrane folds inward around the material forming a vesticle

Question 46

Types of endocytosis

Answer 46

Phagocytosis, pinocytosis, receptor mediated endocytosis

Question 47

Phagocytosis

Answer 47

Eating part - Molecules or entire cells are engulfed. For example a food vacuole or phagosome forms, which fuses with a lysosome

Question 48

Pinocytosis

Answer 48

The drinking part - a vesicle forms to bring small dissolved substances or fluids into a cell

Question 49

Exocytosis

Answer 49

The process by which materials packaged in vesicles are secreted from the cell when the vesicle membrane disused to the cell membrane