Ch 3 - Cell Structure & Function

Question 1

What are the basic principles of the Cell Theory?

Answer 1

1. A cell is the basic unit of life. Nothing smaller than a cell is alive
2. All living organisms are made up entirely of cells
3. New cells arise only from pre-existing cells

Question 2

Why is cell size important?

Answer 2

The smaller the cell, the greater the surface area. This is important because nutrients enter a cell (and waste exits) at the surface of the cell. The more surface area, the more material can enter and exit the cell. Cell division assists with this, as it makes larger cells smaller.

Question 3

What are three different types of microscopes, and how are they different?

Answer 3

1. A compound light microscope = uses light rays passing through the object to magnify them. Can be viewed by human eye
2. Transmission electron microscope = uses a stream of electrons to produce magnified image. Cannot be viewed by human eye. Magnification & resolution of the image, however, is very high…so it can produce larger images with greater detail.
3. Scanning electron microscope = provides a 3-dimensional view of the surface of an object. Narrow beam of electrons is scanned over surface of specimen, which is coated w/ a layer of metal. Metal gives off secondary electrons, which are collected to produce a television-type picture of specimen’s surface on a screen

Question 4

What are the differences between a eukaryotic cell and a prokaryotic cell?

Answer 4

1. Eukaryotic is human/mammal cell, prokaryotic is bacterial cell
2. Eukaryotic have a nucleus, and prokaryotic don’t (their DNA just floats around in the cytoplasm

Question 5

What do all cells have (eukaryotic & prokaryotic)?

Answer 5

1. A plasma membrane
2. Cytoplasm
3. DNA

Question 6

What are the two types of prokaryotic cells?

Answer 6

1. Eubacteria
2. Archaebacteria - known for living in extreme environments that may mirror first environments on earth: too hot, too salty, too acidic for survival of most cells

Question 7

What are the different parts of the nucleus in a eukaryotic cell?

Answer 7

Main role of nucleus = DNA storage

1. Nucleolus = very center of nucleus where ribosomes are formed
2. Chromatin = threads of DNA and protein floating outside of the nucleus
3. Nuclear envelope = double membrane w/ nuclear pores that encloses the nucleus

Question 8

What are the components of the endoplasmic reticulum, and what is their function?

Answer 8

1. Rough ER = attached to the nucleus; responsible for protein production. mRNA attaches to ribosomes, who then begin protein production
2. Smooth ER = lipid production; detoxification

Question 9

What are the final destinations for proteins created in the rough ER (vs. proteins created by ribosomes that float in the cytoplasm)?

Answer 9

Rough ER ribosomes create proteins that usually travel to the Golgi apparatus or the plasma membrane.

Question 10

What is the cytoskeleton, and where is it located?

Answer 10

Located in the cytoplasm. Provides structure to cells, maintains cell shape and assists movement of cell parts.

Question 11

What is the cytoskeleton, and where is it located?

Answer 11

Located in the cytoplasm. Provides structure to cells, maintains cell shape and assists movement of cell parts. Either anchors the organelles or assists their movement as appropriate (i.e. when lysosomes need to engulf something)

Question 12

What is a lysosome?

Answer 12

A vesicle within the cytoplasm of a cell that digests macromolecules and cell parts

Question 13

What is a peroxisome?

Answer 13

A vesicle within the cytoplasm of a cell that destroys lipids

Question 14

What is a centrosome, and what do its contents produce?

Answer 14

It’s a microtubule organizing center that contains a pair of centrioles, which are short cylinders of microtubules. The centrosome also contains a complex of proteins that help form additional microtubules

Question 15

What are ribosomes and polyribosomes?

Answer 15

Ribosomes = particles that carry out protein synthesis
Polyribosomes = a string of ribosomes in the cytoplasm, simultaneously synthesizing the same protein

Question 16

What are ribosomes and polyribosomes?

Answer 16

Ribosomes = particles that carry out protein synthesis. Ribosomes = ribosomal RNA (rRNA) + proteins 
Polyribosomes = a string of ribosomes in the cytoplasm, simultaneously synthesizing the same protein

Question 17

What is the plasma membrane?

Answer 17

It’s a phospholipid bilayer (2 layers of phospholipids).
Polar phosphate molecules face the water, non-polar phosphate molecules lay between the layers to stay away from the water.

Question 18

What is the stance of the fluid-mosaic model?

Answer 18

It’s a working description of the membrane structure of a cell that says that protein molecules form a shifting patterns within the fluid phospholipid bilayer. Cholesterol lends support to the membrane. Short chains of sugars are attached to the outer surface of some protein and lipid molecules.

Question 19

What are the sugars attached to proteins and lipids on a cell membrane called? What is their significance?

Answer 19

Glycoproteins and glycolipids. They’re important because they help mark the cell as belonging to a specific person & account for why people have different blood types. This is how our T-cells can recognize self vs. non-self!!

Question 20

What is diffusion?

Answer 20

RANDOM movement of molecules from high concentration to an area of low concentration. This happens simply based on probability…it’s more probable that molecules will randomly migrate toward low-concentration areas.

Question 21

What is osmosis?

Answer 21

The net movement of water across a semipermeable membrane from area of high concentration to area of low concentration. Because solute can’t pass through the membrane to even out its concentration, water molecules will gravitate toward the side of the membrane where there are more solutes, and they’ll dilute the solute. Solute is dissolved in solvent (usually solvent is water). Tonicity and osmotic pressure control osmosis

Question 22

What is tonicity?

Answer 22

Something that controls osmosis.

Question 23

What is hypotonic, isotonic and hypertonic?

Answer 23

https://drive.google.com/file/d/13WmJ7c5csZhp40JGauLsn1pPwM46XLJU/view?usp=sharing

Question 24

What is facilitated transport?

Answer 24

A molecule is transported across the plasma membrane from the side of higher concentration to the side of lower concentration. Each protein carrier binds to only a particular molecule (i.e. glucose). Type 2 diabetes is when cells lack glucose transporters

Question 25

What is active transport?

Answer 25

When a molecule moves from lower to higher concentration. Requires ATP because it forces a substance against its concentration gradient.

Question 26

What is phagocytosis?

Answer 26

When white blood cells take up pathogens by endocytosis

Question 27

What is pinocytosis?

Answer 27

When cells take up small molecules and fluid

Question 28

What is endocytosis?

Answer 28

When plasma membrane forms a pouch to envelope a substance or fluid

Question 29

What is exocytosis?

Answer 29

When a vesicle fuses with the plasma membrane to secrete substances and fluids. This is how neurotransmitters leave one nerve cell to excite the next nerve or muscle cell.

Question 30

What is transcription?

Answer 30

Creating RNA from DNA. RNA is the messenger for DNA, as DNA never moves places.

Question 31

What is translation?

Answer 31

Making protein from RNA instructions. “Our DNA has the blueprints for every protein in our body.”

Question 32

What is chromatin?

Answer 32

A combination of DNA and proteins

Question 33

During what processes does chromatin form into chromosomes?

Answer 33

Meiosis = cell division that forms reproductive cells in humans
Mitosis = cell division that duplicates cells

Question 34

What role do cilia and flagella play?

Answer 34

They’re cells that are involved in movement. For example, in our respiratory tract we have ciliated cells to sweep mucus back up the throat.

Question 35

How do cilia and flagella move?

Answer 35

Microtubules allow them to interact, bend and, thereby, move as a result of motor molecules.

Question 36

What are the types of cell junctions and why are they important?

Answer 36

Human tissues are known to have junctions between their cells that allow them to function in a coordinated manner.

• Adhesion = cytoskeletons of two cells are interconnected
• Tight = proteins in plasma membranes connect to one another
• Gap = channel proteins create a small hole through which substances can travel and communicate

Question 37

What is cellular respiration? What are the steps in cellular respiration?

Answer 37

The process of producing ATP b/c mitochondria uses up oxygen and gives off carbon dioxide
Steps:
1. Glycolysis
2. Citric Acid Cycle (Krebs cycle)
3. Electron transport chain

Question 38

What is metabolism?

Answer 38

All the chemical reactions that occur in a cell

Question 39

What is feedback inhibition?

Answer 39

A type of metabolic regulation. One of the end products of the metabolic pathway interacts with an enzyme early in the pathway. This slows down the pathway so that the cell doesn’t produce more product than it needs

Question 40

What are coenzymes?

Answer 40

They’re nonprotein molecules that assist the activity of an enzyme and may even accept or contribute atoms to the reaction.

Question 41

What is glycolisis?

Answer 41

The anaerobic pathway of ATP that yields 2 ATP molecules. Because it doesn’t require oxygen, this is the pathway that can occur in microbes living in our guts (that annoying bacteria!). It’s when a sugar molecule is split up to create energy.

Question 42

What is the citric acid cycle?

Answer 42

Krebs cycle. Occurs in the matrix of the mitochondria. To complete the breakdown of glucose from the glycolysis process

Question 43

What is the electron transport chain?

Answer 43

NADH molecules from glycolysis and the citric acid cycle deliver electrons to the ETC. This is aerobic and produces the rest of the ATP molecules (32 of them)

Question 44

What happens when oxygen isn’t available to cells in the electron transport chain?

Answer 44

Fermentation (lactic acid)

Question 45

What happens to ATP when we use it for energy?

Answer 45

ATP is broken down into ADP + phosphate. This gives off energy and heat. ATP = TRIphosphate. ADP = DIphosphate

Question 46

How do we replenish our energy (ATP)?

Answer 46

We add a phosphate back on the ADP to create ATP when we consume food.