Unit 2: Cells & Cellular Transport

Question 1

What are the components of a Phospholipid and their attributes?

Answer 1

Phosphate head, polar and hydrophilic
Fatty Acid tails, no polar and hydrophobic

Question 2

What do Phospholipids make up in the cell?

Answer 2

Plasma cell membrane (bilayer)

Question 3

What does the cell membrane do? (2)

Answer 3

1. separates living cell from aqueous envrionment
2. controlls traffic in & out of the cell (some substances can cross over more easily than others)

Question 4

How are cell membranes semi-permeable?

Answer 4

Only small, no polar molecules are able to pass without assistance (ex. water) and some molecules have protein channels to allow specific material to pass

Question 5

What are the 6 structures embedded in the membrane?

Answer 5

carbohydrate, peripheral protein, integral protein, glycoprotein, cholesterol, glycolipid

Question 6

Role of Cholesterol

Answer 6

• effects flexibility of the membrane
• & of unsaturated fatty acids is what determines the fluidity (more=more fluid)

Question 7

Role of Carbohydrates

Answer 7

• cell-cell recognition
• identification

Question 8

Why are proteins the best to make channels through the membrane?

Answer 8

Can have multiple properties that allows them to pass through the no polar, polar, hydrophilic, and hydrophobic regions of the phospholipids

Question 9

How do amino acids connect to the membrane?

Answer 9

• within membrane: nonpolar, hydrophobic amino acids that anchors into the membrane
• outside of membrane: polar, hydrophilic amino acids extend into the extracellular fluid and into the cytosol

Question 10

What is the name for the water channel?

Answer 10

aquaporin

Question 11

What are the 6 functions of membrane proteins?

Answer 11

transporter, enzyme activity, cell surface receptor, identification marker, cell adhesion, cytoskeleton attachment

Question 12

Role of Peripheral Proteins?

Answer 12

identification markers bound loosely on the membrane

Question 13

Role of Integral Proteins?

Answer 13

penetrates the lipid bilayer as transmembrane proteins that transport proteins as channels or pumps

Question 14

What is Diffusion?

Answer 14

• universe tends toward disorder (entropy)
• movement of particles from high to low concentration

Question 15

What is Simple Diffusion?

Answer 15

• Movement from High to Low Concentration
• passive transport that doesn’t require energy

Question 16

What is Facilitated Diffusion?

Answer 16

• Diffusion through protein channels, specific molecules need the assistance of a channel to pass)
• high to low concentration

Question 17

What is Active Transport?

Answer 17

• protein pump
• requires energy/ATP
• can allow cells to move against the concentration gradient

Question 18

What are the 2 methods to moving large molecules?

Answer 18

Endocytosis and Exocytosis

Question 19

What is Phagocytosis?

Answer 19

the molecules are surrounded by membrane that creates a substance vacuole, which then fuses with a lysosome which contains digestive enzymes
- solid substances

Question 20

What is Pinocytosis?

Answer 20

the molecules are surrounded by membrane that creates a substance vacuole, which then fuses with a lysosome which contains digestive enzymes
- liquid substances

Question 21

What is Receptor-Mediated Endocytosis

Answer 21

similar to Phagocytosis, but is triggered by receptor proteins on the cell surface which capture a specific molecule

Question 22

What is Osmosis?

Answer 22

Diffusion of water

Question 23

Hypertonic

Answer 23

more solute, less water

Question 24

Hypotonic

Answer 24

less solute, more water

Question 25

Isotonic

Answer 25

equal solute, equal water

Question 26

What are the names for animal cells for the 3 different osmolarities?

Answer 26

Hypo: lysed Iso: normal Hyper: shriveled

Question 27

What are the names of the plant cells for the 3 different osmolarities?

Answer 27

Hypo: turgid Iso: Flaccid Hyper: Plasmolyzed

Question 28

What is the solution to possible cell burst due to being in a hypotonic solution?

Answer 28

contractile vacuoles that pumps water out of the cell (ATP)

Question 29

Why can plant cells be placed in hypotonic solutions and animal cells can't?

Answer 29

Plant cells have a cell wall that protects them from bursting. Also, the bigger the vacuole is, the more it is pushing on the cell walls which improves rigidity

Question 30

Solution for a cell being placed in a hypertonic solution?

Answer 30

Absorb more water to have a pump that takes out the solute out of the cell

Question 31

What happens when a plant cell plasmolysizes?

Answer 31

the membrane pulls away from the cell way, causes the cell to shrink and crumple. This also results in wilting since there is less water and is less rigid

Question 32

What state is the cell in when it is placed in a isotonic solution?

Answer 32

equilibrium

Question 33

What is the flow of water when a cell is placed in a isotonic solution?

Answer 33

no net movement of water, flows across the membrane equally in both directions

Question 34

What molecules can pass through the cell membrane directly?

Answer 34

fats and other lipids

Question 35

What molecules can't get through the membrane directly?

Answer 35

polar molecules, charged ions, large molecules

Question 36

What is Water Potential?

Answer 36

Ψ, ability of water to do work, measured in bars

Question 37

What is the Ψ of distilled water?

Answer 37

0

Question 38

What does more solute do to water potential?

Answer 38

makes the Ψ more negative, less likely to do work, meaning a higher chance that it would receive water

Question 39

Osmolarity Definition

Answer 39

- generic term for hypotonic, hypertonic, and isotonic - concentration of a solution expressed as the total number of solute particles per liter

Question 40

What are the 2 factors of water potential?

Answer 40

solute concentration and pressure

Question 41

Why is pressure potential important in plants?

Answer 41

B/c plant cells are surrounded by a strong cell wall which is rigid. As water enters the cell, the volume increases and presses on the cell wall, increasing the pressure. This stops more water from entering the cell and also prevents bursting.

Question 42

What is turgor pressure?

Answer 42

force from within the cell that pushes the plasma membrane against the cell wall created by water moving into the cell via osmosis

Question 43

What is Cytology?

Answer 43

Study of cell structure

Question 44

What is an amphipathic molecule?

Answer 44

Contains both hydrophobic and hydrophilic regions

Question 45

What is a protist?

Answer 45

Unicellular eukaryotes

Question 46

What are 5 features that prokaryotes and eukaryotes share?

Answer 46

Plasma membrane. Cytosol, chromosomes, ribosomes, cytoplasm

Question 47

What are 2 factors that effect cell size?

Answer 47

Surface area - volume ratio metabolic requirements

Question 48

How does surface area to volume ratio effect cell size?

Answer 48

- smaller cells are more efficient compared to bigger cells b/c materials can cross through quicker and there is a higher surface area to volume ratio, meaning the cell can take in more nutrients to sustain a smaller amount

Question 48

How does metabolic requirements effect cell size?

Answer 48

The cell has to be a certain size to fit all the components needed for it to function

Question 49

What are the 2 cellular components involved in the genetic control of the cell?

Answer 49

Nucleus, houses the cell's DNA Ribosome, uses information from the DNA to synthesize proteins

Question 50

What 3 organelles can gene information be found in?

Answer 50

DNA, mitochondria, chloroplasts

Question 51

What is the function of mRNA?

Answer 51

It is synthesized in the nucleus and carries information out of the nucleus into the cytoplasm. It reaches the ribosomes and the ribosomes translate the information into a specific protein

Question 52

What organelles does the Endomembrane system include?

Answer 52

Nuclear envelope, endoplasmic reticulum, Golgi, lysosomes, vesicles, vacuoles

Question 53

What is the function difference between bound and free ribosomes?

Answer 53

Free Ribosomes: produces proteins that function primarily within the cytosol Bound Ribosomes: produces proteins made for insertion into the membrane

Question 54

How does the Smooth ER detoxify substances?

Answer 54

Adds hydroxyl groups to the toxic substances to make them water-soluble and able to e flushed from the body

Question 55

What are the Cis and Trans faces of the Golgi Apparatus?

Answer 55

Cis Face: vesicles add materials to this part of the Golgi Trans Face: vesicles pinch off from the trans face

Question 56

What are the 2 organelles require to work together to aid cell motility?

Answer 56

Cytoskeleton and motor proteins

Question 57

What are the 3 main types of fibers that make up the cytoskeleton?

Answer 57

Microtubules, intermediate filaments, micro filaments

Question 58

How does the percentage of unsaturated fats in the plasma membrane effect the fluidity?

Answer 58

The higher percentage of unsaturated fats present in the membrane means it is more fluid. This is because of the various kinks in the fatty acid tails that prevent the phospholipids from solidifying due to them not being able to get close enough

Question 59

What molecules can pass through the membrane without assistance?

Answer 59

Nonpolar, hydrophobic molecules and lipids

Question 60

What molecules are able to pass slowly through the membrane?

Answer 60

Some polar molecules like water

Question 61

What is Tonicity?

Answer 61

ability of a surrounding solution to cause a cell to gain or lose water

Question 62

What is Osmoregulation?

Answer 62

control of solute concentrations and water balance

Question 63

How does the Cell Wall prevent further water intake when a plant cell is placed in a hypotonic solution?

Answer 63

The pressure from the central vacuole pressing on the cell wall creates turgor pressure which prevents any more water from getting into the cell