HLSC 126 - Physiology > Midterm 1 > Flashcards

Midterm 1 Flashcards

(108 cards)

Study These Flashcards
1
Q

What are the 3 main parts of a eukaryotic cell?

A

plasma membrane, nucleus, cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nucleus

A

control centre of the cell, stores genetic information (DNA), directs cell activity, makes ribosomes

double layered membrane enclosing DNA and proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mitochrondria

A

Site of energy (ATP) production, site of cellular respiration

rod or oval shaped, double membrane, inner membrane folded into cristae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Ribosomes

A

protein synthesis (workbenches of the cell)

small complexes of rRNA and proteins; free in cytoplasm or attached to rough ER.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Endoplasmic Reticulum

A

Rough ER:
- studded with ribosomes
- protein synthesis and processing, sends them to Golgi.

Smooth ER:
- lacks ribosomes
- synthesizes lipids, metabolizes carbohydrates, detoxifies drugs, and stores calcium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Golgi apparatus

A

modifies, packages, ships proteins/lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lyosomes/Peroxisomes

A
  • digestion and detox (Lysol cleans)
  • digestion system of cell, breaks down debris, organelles and foreign material
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Plasma Membrane

A

selective barrier, controls movement in/out, maintains stability

Acts as a selective barrier controlling what enters and exits the cell; involved in cell signaling and recognition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain the structure and dynamic nature of the plasma membrane.

A

fluid mosaic model: phospholipids, proteins, cholesterol

selective permeability: allows control of what enters/exits

membrane proteins: channels, carriers, receptors, enzymes

The plasma membrane follows the fluid mosaic model (made of phospholipids, proteins, and cholesterol). It has selective permeability, controlling what enters and exits the cell. Membrane proteins act as channels (open passageways), carriers (transport specific molecules), receptors (receive signals), and enzymes (speed up reactions).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is passive transport?

A

Movement down the concentration gradient (high → low) without energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give two examples of passive transport.

A

Simple diffusion and facilitated diffusion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is diffusion?

A

Net movement of molecules from high → low concentration until equilibrium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is osmosis?

A

Passive diffusion of water across a membrane from low solute (high water) → high solute (low water).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Is facilitated diffusion active or passive?

A

Passive (no energy required).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does facilitated diffusion require?

A

A carrier or channel protein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give an example of a molecule that uses facilitated diffusion.

A

Glucose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is active transport?

A

Movement against the concentration gradient (low → high) that requires energy (ATP).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Example of active transport?

A

Sodium-potassium pump (Na⁺ out, K⁺ in using ATP).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the sodium-potassium (Na⁺/K⁺) pump do?

A

Pumps 3 Na⁺ out and 2 K⁺ in, against their gradients, using ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is ATP required for the Na⁺/K⁺ pump?

A

ATP phosphorylation drives conformational changes that move ions uphill.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is vesicular transport?

A

A type of active transport that uses vesicles to move large substances across the membrane. Requires energy (ATP).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is endocytosis?

A

Vesicular transport that brings substances into the cell.

Examples: phagocytosis = “cell eating,” pinocytosis = “cell drinking.”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is exocytosis?

A

Vesicular transport that expels substances from the cell using vesicles.

Example: secretion of hormones or neurotransmitters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is passive transport?

A

Movement down the concentration gradient (high → low) without energy.

Depends on concentration gradient, no ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is active transport?
Movement against the concentration gradient (low → high) that requires energy (ATP). ## Footnote Depends on concentration gradient + ATP use.
26
What does facilitated diffusion require?
A carrier or channel protein. ## Footnote Depends on transport proteins, but no ATP.
27
What does the sodium-potassium (Na⁺/K⁺) pump do?
Pumps 3 Na⁺ out and 2 K⁺ in, against their gradients, using ATP. ## Footnote Depends on ATP energy + specific pump protein.
28
What is unassisted membrane transport?
Movement across the membrane without help from proteins. Includes simple diffusion and osmosis.
29
What is diffusion?
Net movement of molecules from high → low concentration until equilibrium. - molecules move down the gradient (O2, C02)
30
What molecules move by simple diffusion?
Small nonpolar molecules (O₂, CO₂, fatty acids, steroids).
31
What is osmosis?
Passive diffusion of water across a membrane from low solute (high water) → high solute (low water).
32
What is osmotic pressure?
The pulling pressure that draws water toward the side with higher solute concentration.
33
What factors affect diffusion rate?
Fick’s Law: higher concentration gradient, higher surface area, shorter distance, higher permeability = faster diffusion.
34
What is osmosis?
Passive diffusion of water across a membrane from low solute (high water) → high solute (low water).
35
What is osmotic pressure?
The pulling force that draws water to the side with higher solute concentration.
36
What solution causes a cell to shrink (crenate)?
A hypertonic solution (water moves out by osmosis).
37
What solution causes a cell to swell/burst (lyse)?
A hypotonic solution (water moves in by osmosis).
38
What solution leaves a cell unchanged?
An isotonic solution (water moves in and out equally by osmosis).
39
What is diffusion?
Net movement of molecules from high → low concentration until equilibrium.
40
What is simple diffusion?
Passive movement directly through the lipid bilayer, without proteins or energy. - molecules move down gradient (O2, C02)
41
What molecules move by simple diffusion?
Small, nonpolar molecules like O₂, CO₂, fatty acids, and steroids.
42
What factors affect diffusion rate?
depends on size, lipid solubility, gradient Concentration gradient, membrane permeability, surface area, distance, and molecular size (Fick’s Law).
43
What is vesicular transport?
A type of active transport that uses vesicles and ATP to move large substances across the membrane.
44
What is endocytosis?
Vesicular transport that brings substances into the cell (phagocytosis = “cell eating,” pinocytosis = “cell drinking”).
45
What is exocytosis?
Vesicular transport that expels substances from the cell using vesicles (e.g., secretion of hormones, neurotransmitters, enzymes).
46
How does vesicular transport support secretion?
Exocytosis packages materials into vesicles and fuses them with the membrane to release substances outside the cell.
47
How does vesicular transport support uptake?
Vesicular transport = movement using little “bubbles” (vesicles) made from the plasma membrane Uptake = bringing them into the cell Examples: phagocytosis (cell eating particles), pinocytosis (cell drinking) Endocytosis brings large particles, fluids, or molecules into the cell by forming vesicles from the plasma membrane.
48
What is the fluid mosaic model?
The fluid mosaic model describes the structure of the plasma membrane as a mosaic of various components that move fluidly within the layer.
49
What components make up the plasma membrane?
Phospholipids, proteins, and cholesterol.
50
How are phospholipids arranged in the membrane?
Phospholipids are arranged in a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.
51
Which part of a phospholipid is hydrophilic? Which is hydrophobic?
The head is hydrophilic, and the tails are hydrophobic.
52
What role does cholesterol play in the membrane?
Cholesterol helps to stabilize the membrane's fluidity and structure.
53
What are the functions of membrane proteins?
Membrane proteins function as channels, carriers, receptors, and enzymes.
54
What does facilitated diffusion require?
Facilitated diffusion requires a channel or carrier protein.
55
What do carbohydrates on the plasma membrane do?
Carbohydrates contribute to the glycocalyx, recognition, adhesion, and communication.
56
What does selective permeability mean?
Selective permeability refers to the ability of the membrane to allow certain substances to cross while blocking others.
57
What factors determine what can cross the membrane?
Factors include size, polarity, gradient, and need for energy.
58
In a membrane model, what do the two layers with tails in the middle represent?
Phospholipid bilayer (hydrophilic heads outside, hydrophobic tails inside).
59
In a membrane model, what do the yellow blobs between phospholipids represent?
Cholesterol (stabilizes and regulates fluidity).
60
In a membrane model, what do tube- or gate-like structures across the bilayer represent?
Membrane proteins (channels or carriers for transport).
61
In a membrane model, what do chains sticking out of the membrane surface represent?
Carbohydrates/glycocalyx (cell recognition and communication).
62
Is facilitated diffusion active or passive?
Passive (no energy required).
63
What does facilitated diffusion require?
A carrier or channel protein.
64
Give an example of a molecule that uses facilitated diffusion.
Glucose.
65
What is active transport?
Movement against the concentration gradient (low → high) that requires energy (ATP).
66
Example of active transport?
Sodium-potassium pump (Na⁺ out, K⁺ in using ATP).
67
What does the sodium-potassium (Na⁺/K⁺) pump do?
Pumps 3 Na⁺ out and 2 K⁺ in, against their gradients, using ATP.
68
Why is ATP required for the Na⁺/K⁺ pump?
ATP phosphorylation drives conformational changes that move ions uphill.
69
What is secondary active transport?
Uses energy stored in ion gradients to move substances (indirectly powered by ATP).
70
What is symport in secondary active transport?
A carrier protein moves two molecules in the same direction across the membrane (e.g., glucose + Na⁺).
71
What are gap junctions?
Channels that connect adjacent cells, allowing ions and small molecules to pass directly between them. *direct cell communication
72
What is cell-to-cell recognition?
When surface molecules on one cell act as signals and are recognized by another cell. *direct cell communication
73
What is indirect cell communication?
Cells release chemical messengers (ligands) that bind to receptors on target cells.
74
What are paracrines?
Local chemical messengers that act on nearby cells.
75
What are neurotransmitters?
Chemical messengers released by neurons that act on adjacent cells.
76
What are hormones?
Chemical messengers released into the blood to act on distant target cells.
77
What are neurohormones?
Messengers released by neurons into the blood to act on distant targets.
78
What is signal transduction?
The process where a ligand binds to a receptor, triggering intracellular events that produce a response in the target cell.
79
What types of membrane proteins act as receptors?
Channel-linked receptors, enzyme-linked receptors, and G protein–coupled receptors.
80
How would you explain simple diffusion in your own words?
Molecules slip straight through the membrane from high to low concentration. No protein, no energy.
81
How would you explain facilitated diffusion in your own words?
Molecules still move from high to low concentration, but they need a protein channel or carrier to help them cross. No energy required.
82
How would you explain active transport in your own words?
Molecules move from low to high concentration. This goes “uphill” so it needs ATP energy and a pump protein (like Na⁺/K⁺ pump).
83
Example of simple diffusion across the plasma membrane?
Oxygen (O₂) moving into a cell.
84
Example of facilitated diffusion across the plasma membrane?
Glucose uptake via a carrier protein.
85
Example of active transport across the plasma membrane?
Sodium–potassium (Na⁺/K⁺) pump: moves 3 Na⁺ out and 2 K⁺ in using ATP.
86
What role does cholesterol play in the membrane?
Keeps the membrane stable and regulates fluidity.
87
What does facilitated diffusion require?
A carrier or channel protein.
88
Which part of a phospholipid is hydrophilic? Which is hydrophobic?
Heads are hydrophilic, tails are hydrophobic.
89
Which of the following best describes the structure of the plasma membrane?
Phospholipid bilayer with proteins, cholesterol, and carbohydrates.
90
Which part of a phospholipid is hydrophobic?
Fatty acid tails.
91
What is the role of cholesterol in the plasma membrane?
Stabilizes membrane fluidity and flexibility.
92
Which of the following is an example of a membrane protein functioning as a receptor?
Insulin receptor binding insulin.
93
Carbohydrate chains on the outer surface of the plasma membrane primarily function in:
Cell recognition and communication.
94
What is the main role of epithelial tissue?
To line surfaces, cover organs, and form glands.
95
What is the epithelium of the digestive tract specialized for?
Absorbing nutrients.
96
What is the epithelium of the skin called?
The epidermis.
97
What is the function of the skin’s epithelium?
Protection; it allows very little exchange.
98
What does “lumen” mean in anatomy?
The inner space of a hollow organ, lined by epithelium.
99
What are the main functions of connective tissue?
Connect, support, and protect other tissues.
100
What makes connective tissue unique compared to epithelium or muscle?
It has living cells plus a non-living matrix (fibers + ground substance).
101
What is the main cell of connective tissue?
Fibroblast.
102
What is the role of fibroblasts?
Make fibers, divide, and form new connective tissue.
103
What do macrophages do in connective tissue?
Provide defense by engulfing (phagocytosing) foreign material.
104
What do lymphocytes do in connective tissue?
Provide immune defense.
105
Which fibers give strength (e.g., in tendons)?
Collagen fibers.
106
Which fibers allow stretch and recoil (e.g., in lungs)?
Elastic fibers.
107
Which fibers form a supportive framework in lymph nodes?
Reticular fibers (thin collagen strands).
108
What is homeostasis?
The ability of an organism to keep the inside of the body stable, despite changes in the external environment
HLSC 126 - Physiology
flashcards
Decks in class (9)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions