Module 2.1 & 2.2: Cellular Physiology- Cell Membrane And Organelles

Question 1

What is cell theory

Answer 1

Cells are the smallest unit of life and the building blocks of all organisms, arise from pre-existing cells, are similar in structure and function, function depends on structural properties, and an organisms structure and function depend on the structure and function of its cells

Question 2

What are the three major subdivisions of cells

Answer 2

Plasma membrane, nucleus, and cytoplasm

Question 3

Describe the phospholipids that make up the phospholipid bi- layer of a plasma membrane

Answer 3

The heads contain phosphate which usually has a negative charge, as well as choline and glycerol. It is polar and hydrophilic. The tails contain fatty acid, are nonpolar, and hydrophobic

Question 4

What word describes a molecule that has both hydrophilic and hydrophobic parts

Answer 4

Amphipathic

Question 5

What types of molecules can pass easily through a plasma membrane

Answer 5

Lipid soluble and small molecules such as o2 and h2o, whereas H2O soluable and a large molecules cannot

Question 6

How do cholesterol molecules in the plasma membrane work to affect fluidity, stability, and permeability of the membrane

Answer 6

In cold conditions it increases permeability, whereas in high temperatures when membrane is too fluid it makes the membrane more compact

Question 7

How do carbohydrate molecules interact with plasma membrane

Answer 7

They attach either to phospholipids making a glycolipid, or to proteins making a glycoprotein. Collectively these make up the glycocalyx of a cell, and most have a negative charge

Question 8

Where in the cell are ribosomes synthesized and assembled

Answer 8

In the nucleolus found within the nucleus

Question 9

What occurs in the Endo plasmic reticulum of a cell

Answer 9

Synthesis of proteins in the rough, lipids and enzymes in the smooth, and transportation of these. Forms new cell membrane and other cell components and manufactures products for secretion

Question 10

What occurs in the Golgi complex of a cell

Answer 10

Receives proteins, lipids, and materials from endoplasmic reticulum and modifies, sorts, packs, and distributes proteins. Renews and modifies plasma membrane.

Question 11

From the Golgi complex, where do lysosomes go

Answer 11

Some go to the cell membrane, while other vesicles go outside of the cell such as with insulin

Question 12

What are lysosomes

Answer 12

Membraneous sacs containing hydrolytic enzymes that break down proteins and cellular debris. Digestive system of cell, these pinch off from the Golgi

Question 13

What are the paired, small, barrel shaped organelle with nine short sets of triplet microtubules, and what is their role

Answer 13

The centriole, grows new microtubules and organizes the microtubules of the cytoskeleton

Question 14

What are peroxisome’s

Answer 14

Sacs with a lipid bilayer that contain oxidative enzymes. Break down fatty acid and organic compounds, producing hydrogen peroxide which is further degraded by catalase into water and oxygen. Detoxifies, helps the liver and kidneys by breaking down hydrogen peroxide

Question 15

What makes the mitochondria of a cell so important

Answer 15

Its ability to produce adenosine triphosphate (ATP), the fact that it contains enzymes for the citric acid cycle and electron transport chain, and that it maintains, replicates, and transcribed its own DNA and translates mRNA into protein

Question 16

What are vaults within a cell

Answer 16

Hollow octagonal barrels for transport from nucleus to cytoplasm

Question 17

What is the difference between cytosol and cytoplasm

Answer 17

Cytoplasm includes everything within the walls of the cell membrane other than the nucleus, and cytosol is the gel like portion of the cytoplasm

Question 18

What do the intermediary metabolism enzymes found inside a cell facilitate

Answer 18

Intracellular reactions like degradation, synthesis, and transportation of small organic molecules. Intermediary metabolism occurs mostly in cytosol, and is a large set of chemical reactions needed to capture energy for cell activities and provide raw material for maintaining cell structure and function and growth

Question 19

What are ribosomes, and where can they be found in the cell

Answer 19

Ribosomes are proteins and nucleic acid, and they synthesize proteins. They are found in the cytosol and in the endoplasmic reticulum

Question 20

What type of vesicles are found in cytosol and describe in general

Answer 20

Transport, secretory, and endocytotic, these are transiently formed, membrane enclosed products, synthesized within or engulfed by the cell. They transport and/or store products being moved within, out of, or into the cell respectively

Question 21

Describe the inclusions found inside cytosol in general and give some examples

Answer 21

These store excess nutrients, are nonliving, and have no membrane. Examples are glycogen granules and fat droplets

Question 22

In general, what are the roles of the cytoskeleton portion of a cell

Answer 22

Structural support, movement of the cell, and transport of substances inside the cell

Question 23

Name the three components of a cytoskeleton (the cytoskeletal filaments)

Answer 23

Microtubules, micro filaments, and intermediate filaments

Question 24

What are the cytoskeletal filaments composed of

Answer 24

Protein

Question 25

Describe microtubules and their role in the cell

Answer 25

Long slender hollow tubes composed of secretory vesicles and tubulin. Contribute to cell strength and rigidity, maintains shape, anchors, and moves organelles, forms cilia and flagella, and forms miotic spindle during cell division. Transports secretory vesicles

Question 26

Describe microfilaments and their role in the cell

Answer 26

Helical actin molecules. Involved in cellular contractile systems and mechanical stiffener of micro villi. Anchors cytoskeleton to plasma membrane, aids in gross movement of cell, forms microvilli? Helps pinch cell off for division.

Question 27

Describe intermediate filaments and their role in the cell

Answer 27

Irregular, threadlike, composed of various proteins, also helix? These resist mechanical stress and provide structural support, like springs inside a mattress. Permanent, can’t grow longer and shorter like the other two can

Question 28

Compare the cytoskeletal filaments in regards to size

Answer 28

Microtubules have the largest diameter, microfilaments have the smallest diameter, and intermediate filaments are in the middle

Question 29

In general, what role does the lipid bilayer, proteins, and carbohydrates have in the plasma membrane

Answer 29

The lipid bilayer acts as a barrier to diffusion, proteins perform specific functions, and carbohydrates are self recognition molecules for cell to cell interaction

Question 30

In a plasma membrane, what do proteins act as

Answer 30

Channels for small water soluble substances such as the sodium potassium channel, carrier molecules for substances that cannot cross on their own, docking marker acceptors, membrane bound enzymes, receptor sites, cell adhesion molecules, signalling molecules, and interactors with glycol proteins to recognize self

Question 31

What do proteins acting as inner membrane surface docking marker acceptors do

Answer 31

They bind lock and key style with the docking markers of secretory vesicles, triggering secretion

Question 32

What do membrane bound enzymes do

Answer 32

Control specific chemical reactions at inner or outer cell surface. Cells are specialized in what type they have

Question 33

How do proteins in the plasma membrane act as a receptor sites

Answer 33

They recognize and bind only with specific molecules in the environment, which initiates certain events

Question 34

What do proteins in the plasma membrane acting as cell adhesion molecules (CAM) do

Answer 34

Protrude from outer membrane surface to grip cells together, for example cadherins which act like a zipper and integrins which span the plasma membrane. Some also act as signalling molecules which signal cells to grow and immune system cells to interact

Question 35

What do the short chains of sugar on the outer surface of a cell do for that cell

Answer 35

These carbohydrates are unique for identification of self and other cells. Helpful in tissue growth