Lecture 2 - Cells: The living units

Question 1

How are cells diverse?

Answer 1

Types differ in size, shape, and subcellular components; these differences lead to differences in functions

Question 2

Which of the following is NOT a basic part of a human cell?

A) Plasma membrane
B) Cytoplasm
C) Mitochondria
D) Nucleus

Answer 2

Answer: C (Mitochondria is an organelle, not a basic part of the cell structure)

Question 3

The principle that the structure and function of a cell are complementary is called:

A) Biochemical Function
B) Generalized Cell Theory
C) Structure-Function Complementarity
D) Homeostasis

Answer 3

Answer: C

Question 4

Heat and visible light are most associated with which form of energy?

electrical energy

chemical energy

mechanical energy

radiant energy

none of the above

Answer 4

radiant energy

Question 5

Starch is:

Question 2 options:

a monosaccharide used by plants as fuel source

a fatty acid used by plants as a fuel source

a polymer of amino acids used by animals as a fuel source

a stored form of carbohydrate used by plants

none of the above

Answer 5

a stored form of carbohydrate used by plants - specifically polysachrides

Question 6

Which of the following is incorrect regarding carbohydrates, lipids, proteins and nucleic acids?

they are all considered organic compounds

they are all essential foundations of life

they all contain carbon

they all form polymers by binding to glycerol

Answer 6

they all form polymers by binding to glycerol

Question 7

Which of the following bonds demonstrates electronegativity due to an unequal sharing of electrons between two atoms?

the bonds between sodium and chloride in a salt crystal

the bonds between oxygen and hydrogen within a water molecule

the bonds between oxygen and hydrogen that allow two water molecules to join

the bonds between oxygen and carbon in a carbon dioxide molecule

none of the above

Answer 7

Answer: the bonds between oxygen and hydrogen within a water molecule

Question 8

Unlike triglycerides, phospholipids:

do not contain fatty acids

do not contain glycerol

do not contain carbons bound to hydrogens

have portions that are polar

none of the above

Answer 8

Answer: have portions that are polar

Question 9

Which of the following does NOT belong in a molecule of DNA?

pentose

phosphorus

nitrogen

purines

Answer 9

purines

Question 10

The passage of a fatty acid through a cell membrane is an example of:

facilitated diffusion

active transport

carrier-mediated facilitated diffusion

osmosis

none of the above

Answer 10

Answer: none of the above

its simple diffusion

Question 11

Proteins can be:

classified as integral

receptors

channels

enzymes

all of the above

Answer 11

all of the above

Question 12

The sodium-potassium pump is an example of a symporter that promotes primary active transport.

True
False

Answer 12

False

The sodium-potassium pump is an antiporter (not a symporter) because it transports sodium (Na⁺) out of the cell and potassium (K⁺) into the cell, in opposite directions. It is, however, an example of primary active transport, as it uses ATP directly to function.

Question 13

A solution that can cause cell lysis by driving water into a cell is:

hypotonic

isotonic

hypertonic

hyperosmotic

Answer 13

hypotonic

Question 13

The act of bringing fluid into a cell is most associated with:

phagocytosis

receptor-mediated endocytosis

pinocytosis

exocytosis

none of the above

Answer 13

Answer: Pinocytosis

Question 14

Assuming normal resting membrane potential of a cell, if potassium were to leak down its concentration gradient, the result would be:

the inside of the cell would become more negative

potassium would leave the cell

the inside of the cell would become more positive

potassium would enter the cell

A and B

C and D

Answer 14

A and B

Question 15

New transport vesicles pinch off of the trans face of:

the smooth ER

the rough ER

the Golgi apparatus

the lysosome

none of the above

Answer 15

the Golgi apparatus

Question 16

plasma membrane proteins and phospholipids are synthesized:

in the rough endoplasmic reticulum

in the smooth endoplasmic reticulum

in the Golgi apparatus

in the peroxisome

Answer 16

in the rough endoplasmic reticulum

Question 17

If a cell has a resting membrane potential (RMP) of -90 mV, the opening of a sodium channel can bring the RMP to:

Question 15 options:

-70 mV

-100 mV

-180 mV

-200 mV

none of the above

Answer 17

Answer: -70 mV

Question 18

How many different types of human cells are estimated to exist?

A) 100
B) 250
C) 500
D) Over 250

Answer 18

Answer: D) Over 250

Question 19

Which of the following best describes the plasma membrane?

A) A rigid structure that provides support
B) A flexible outer boundary that acts as a barrier
C) A solid layer preventing any movement of substances
D) None of the above

Answer 19

Answer: B) A flexible outer boundary that acts as a barrier

Question 20

What is the term used to describe the unique pattern formed by membrane proteins and lipids in the plasma membrane?

A) Fluid mosaic model
B) Rigid structure model
C) Semi-permeable model
D) Lipid bilayer model

Answer 20

Answer: A) Fluid mosaic model

Question 21

Which type of membrane protein is primarily involved in cell-to-cell recognition?

A) Integral proteins
B) Peripheral proteins
C) Glycoproteins
D) Lipids

Answer 21

Answer: C) Glycoproteins

Question 22

What type of transport involves the movement of molecules down their concentration gradient without the use of ATP?

A) Active transport
B) Passive transport
C) Vesicular transport
D) Facilitated diffusion

Answer 22

Answer: B) Passive transport

Question 23

Which of the following describes a hypertonic solution?

A) Has a lower osmolarity than the inside of the cell
B) Causes water to enter the cell
C) Has the same osmolarity as the inside of the cell
D) Has a higher osmolarity than the inside of the cell

Answer 23

Answer: D) Has a higher osmolarity than the inside of the cell

Question 24

What is the primary function of the sodium-potassium pump? A) To transport glucose into the cell B) To maintain the resting membrane potential C) To facilitate the uptake of oxygen D) To remove waste from the cell

Answer 24

Answer: B) To maintain the resting membrane potential

Question 25

Which organelle is primarily responsible for ATP production? A) Ribosome B) Nucleus C) Mitochondria D) Golgi apparatus

Answer 25

Answer: C) Mitochondria

Question 26

What type of endocytosis is referred to as "cell eating"? A) Pinocytosis B) Receptor-mediated endocytosis C) Phagocytosis D) Exocytosis

Answer 26

Answer: C) Phagocytosis

Question 27

Which component of the cytoplasm contains the cell's organelles? A) Cytosol B) Inclusions C) Cytoplasmic matrix D) Cytoplasmic organelles

Answer 27

Answer: A) Cytosol

Question 28

True or False: The plasma membrane is a static structure and does not change shape.

Answer 28

Answer: False (The plasma membrane is dynamic and has a fluid mosaic structure.)

Question 29

True or False: Active transport processes do not require energy.

Answer 29

Answer: False (Active transport requires energy, usually in the form of ATP.)

Question 30

True or False: Osmosis specifically refers to the movement of solutes across a selectively permeable membrane.

Answer 30

Answer: False (Osmosis refers to the movement of water across a selectively permeable membrane.)

Question 31

True or False: The rough endoplasmic reticulum is studded with ribosomes and is involved in protein synthesis.

Answer 31

Answer: True

Question 32

True or False: The lysosomes are responsible for detoxifying harmful substances within the cell.

Answer 32

Answer: False (Lysosomes contain digestive enzymes for breaking down waste; peroxisomes detoxify harmful substances.)

Question 33

True or False: The nuclear envelope consists of a single membrane barrier.

Answer 33

Answer: False (The nuclear envelope consists of a double-membrane barrier.)

Question 34

True or False: Glycocalyx is composed of proteins and is found on the surface of the plasma membrane.

Answer 34

Answer: False (Glycocalyx consists of sugars (carbohydrates) sticking out of the cell surface.)

Question 35

True or False: Membrane potential is generated by the separation of charged particles across the plasma membrane.

Answer 35

Answer: True

Question 36

True or False: Secondary active transport directly uses ATP to transport substances across the plasma membrane.

Answer 36

Answer: False (Secondary active transport relies on the ion gradients established by primary active transport.)

Question 37

True or False: Ribosomes are the site of lipid synthesis in the cell.

Answer 37

Answer: False (Ribosomes are the site of protein synthesis.)

Question 38

What are the three basic parts of human cells? A) Cytoplasm, Cell wall, Nucleus B) Plasma Membrane, Cytoplasm, Nucleus C) Endoplasmic Reticulum, Golgi Apparatus, Mitochondria D) Ribosomes, Lysosomes, Cytoskeleton

Answer 38

Answer: B) Plasma Membrane, Cytoplasm, Nucleus

Question 39

Which type of membrane protein spans the entire membrane and has hydrophobic and hydrophilic regions? A) Peripheral proteins B) Integral proteins C) Glycoproteins D) Cholesterol

Answer 39

Answer: B) Integral proteins

Question 40

Which structure is responsible for modifying, concentrating, and packaging proteins and lipids from the rough ER? A) Ribosomes B) Golgi apparatus C) Mitochondria D) Lysosomes

Answer 40

Answer: B) Golgi apparatus

Question 41

What type of solution causes a cell to swell due to water entering? A) Isotonic solution B) Hypotonic solution C) Hypertonic solution D) Saturated solution

Answer 41

Answer: B) Hypotonic solution

Question 42

Which organelle contains powerful detoxifying enzymes and is involved in breaking down fatty acids? A) Mitochondria B) Peroxisomes C) Golgi apparatus D) Endoplasmic reticulum

Answer 42

Answer: B) Peroxisomes

Question 43

What is the primary role of the smooth endoplasmic reticulum? A) Protein synthesis B) Lipid metabolism and detoxification C) Energy production D) Digestion of cellular debris

Answer 43

Answer: B) Lipid metabolism and detoxification

Question 44

Which of the following correctly describes primary active transport? A) It moves substances down their concentration gradient. B) It directly uses ATP to pump solutes across the membrane. C) It involves vesicular transport. D) It does not require any energy.

Answer 44

Answer: B) It directly uses ATP to pump solutes across the membrane.

Question 45

The 'resting membrane potential' (RMP) is primarily influenced by the concentration of which ion? A) Na+ B) Ca²+ C) K+ D) Cl-

Answer 45

Answer: C) K+

Question 46

What type of signaling occurs when a ligand binds to a receptor and triggers a cascade of cellular responses? A) Contact signaling B) Chemical signaling C) Electrical signaling D) Mechanical signaling

Answer 46

Answer: B) Chemical signaling

Question 47

What structure is referred to as the 'cell's internal framework'? A) Cytoplasm B) Cytoskeleton C) Plasma membrane D) Nucleus

Answer 47

Answer: B) Cytoskeleton

Question 48

True or False: The cytoplasm is composed only of the cytosol.

Answer 48

Answer: False (The cytoplasm consists of cytosol, inclusions, and organelles.)

Question 49

True or False: Facilitated diffusion requires energy to transport molecules across the plasma membrane.

Answer 49

Answer: False (Facilitated diffusion does not require energy; it relies on concentration gradients.)

Question 50

True or False: Glycolipids contribute to the cell's ability to recognize other cells.

Answer 50

Answer: True

Question 50

True or False: The nucleus is responsible for producing ATP for the cell.

Answer 50

Answer: False (The mitochondria are responsible for ATP production.)

Question 51

True or False: All cells have the same structure and function.

Answer 51

Answer: False (Different types of cells have variations in structure and function.)

Question 52

True or False: Exocytosis is the process of transporting materials out of the cell.

Answer 52

Answer: True

Question 53

True or False: Cholesterol is found in the plasma membrane and increases its fluidity.

Answer 53

Answer: False (Cholesterol increases the stability of the membrane, making it less fluid.)

Question 54

True or False: Receptor-mediated endocytosis is a non-selective process.

Answer 54

Answer: False (Receptor-mediated endocytosis is selective as it depends on the binding of substances to specific receptors.)

Question 55

True or False: The term 'tonicity' refers to the osmotic pressure of a solution relative to the cell.

Answer 55

Answer: True

Question 56

True or False: The cytoskeleton consists only of microfilaments.

Answer 56

Answer: False (The cytoskeleton consists of microfilaments, intermediate filaments, and microtubules.)

Question 57

What is the primary function of lysosomes? a) Protein synthesis b) ATP production c) Digestion of waste materials and cellular debris d) Synthesis of lipids

Answer 57

Answer: c) Digestion of waste materials and cellular debris

Question 58

What type of endocytosis involves the engulfing of large particles or cells? a) Pinocytosis b) Phagocytosis c) Receptor-mediated endocytosis d) Exocytosis

Answer 58

Answer: b) Phagocytosis

Question 59

Which of the following is NOT a function of the smooth endoplasmic reticulum? a) Lipid metabolism b) Detoxification of drugs c) Protein synthesis d) Storage and release of calcium

Answer 59

Answer: c) Protein synthesis

Question 60

The cytoskeleton is primarily made up of which of the following components? a) Glycolipids and phospholipids b) Microfilaments, intermediate filaments, and microtubules c) Ribosomal RNA and proteins d) Vesicles and lysosomes

Answer 60

Answer: b) Microfilaments, intermediate filaments, and microtubules

Question 61

What is the primary role of the Golgi apparatus in the cell? a) Synthesis of lipids b) Modifying, concentrating, and packaging proteins c) ATP production d) Detoxification of harmful substances

Answer 61

Answer: b) Modifying, concentrating, and packaging proteins

Question 62

What component of the glycocalyx plays a crucial role in cell recognition? a) Lipids b) Proteins c) Carbohydrates d) Nucleic acids

Answer 62

Answer: c) Carbohydrates

Question 62

In receptor-mediated endocytosis, what must occur for the substance to be pulled into the cell? a) The substance must diffuse through the lipid bilayer. b) The substance must bind to its unique receptor on the cell surface. c) The substance must undergo phagocytosis. d) The substance must activate the smooth endoplasmic reticulum.

Answer 62

Answer: b) The substance must bind to its unique receptor on the cell surface.

Question 63

True or False: The primary function of ribosomes is to synthesize ATP.

Answer 63

Answer: False

Question 64

True or False: The membrane potential is primarily determined by the movement of sodium (Na+) and potassium (K+) ions across the plasma membrane.

Answer 64

Answer: True

Question 65

True or False: Phagocytosis is a form of endocytosis that is specific to fluid uptake.

Answer 65

Answer: False

Question 66

True or False: The Golgi apparatus modifies and packages proteins for secretion from the cell.

Answer 66

Answer: True

Question 67

True or False: The cytoplasm includes the cytosol, organelles, and inclusions.

Answer 67

Answer: True

Question 68

True or False: Integral proteins are loosely attached to the plasma membrane.

Answer 68

Answer: False

Question 69

True or False: The primary role of peroxisomes is to detoxify harmful substances.

Answer 69

Answer: True