Cells Flashcards
(83 cards)
1
Q
What is the term for the state of balance within the body?
A
Homeostasis
2
Q
What are the basic activities of a human body?
A
- Maintenance of boundaries
- Movement
- Digestion
- Excretion
- Growth
- Repair
- Responsiveness
- Metabolism
- Reproduction
3
Q
What are the levels of structural complexity of the human body?
A
- Atoms
- Molecules
- Cells
- Tissues
- Organs
- Systems
- Organism
4
Q
What does homeostasis breakdown lead to?
A
Disease
5
Q
What are the two types of body fluids in homeostasis?
A
- Extracellular fluid (ECF)
- Intracellular fluid (ICF)
6
Q
What mechanism dampens the intensity of the original stimulus in homeostasis?
A
Negative feedback mechanisms
7
Q
What is an example of a positive feedback mechanism?
A
Inflammatory response to infection
8
Q
What is the anatomical position?
A
Standing upright, facing the observer, head level, eyes forward, feet flat, arms at sides, palms forward
9
Q
What is a sagittal plane?
A
Divides the body into left and right sides
10
Q
What does the frontal (coronal) plane divide?
A
Divides the body into front (anterior) and back (posterior) portions
11
Q
What is the definition of proximal?
A
Nearer to the attachment of the limb to the trunk
12
Q
What is the definition of distal?
A
More distant from the attachment of the limb to the trunk
13
Q
What are the two major body cavities?
A
- Dorsal body cavity
- Ventral body cavity
14
Q
What does the thoracic cavity contain?
A
- Heart
- Oesophagus
- Trachea
- Major blood vessels
15
Q
What type of membrane covers organs within body cavities?
A
Serous membrane
16
Q
What are the three key components of the cell?
A
- Plasma membrane
- Cytoplasm
- Nucleus
17
Q
What is the function of the plasma membrane?
A
- Acts as a barrier
- Controls flow of substances
- Identifies the cell
- Participates in intercellular signaling
18
Q
What comprises 75% of the cell membrane lipids?
A
Phospholipids
19
Q
Fill in the blank: A plane is an _______ flat surface that passes through the body.
A
imaginary
20
Q
True or False: The mid-sagittal plane produces unequal halves.
A
False
21
Q
What does ‘ospho’ refer to?
A
Contains a phosphate group
22
Q
Define ‘lipid’.
A
Fatty compound
23
Q
What does ‘amphi’ mean in the context of ‘amphipathic’?
A
Both
24
Q
What does ‘pathic’ refer to in ‘amphipathic’?
A
Condition
25
What is the meaning of 'philos'?
To love
26
What does 'phobia' translate to?
To fear
27
What percentage of cell membrane lipids do phospholipids comprise?
75%
28
What is a phospholipid bilayer?
2 parallel layers of molecules
29
What does 'amphipathic' mean?
Has both a polar and a non-polar region
30
What are the polar parts of phospholipids called?
Heads
31
What are the non-polar parts of phospholipids called?
Tails
32
What is the nature of the polar parts (heads) of phospholipids?
Hydrophilic
33
What is the nature of the non-polar parts (tails) of phospholipids?
Hydrophobic
34
What percentage of cell membrane lipids does cholesterol comprise?
20%
35
What role does cholesterol play in the plasma membrane?
Used in steroid hormone synthesis
36
What is the structure of cholesterol?
Rigid ring structure
37
What does cholesterol do to phospholipid tails?
Stops them from associating too tightly or loosely; maintains fluidity
38
What types of molecules can cross the lipid bilayer?
Nonpolar, uncharged molecules (e.g., O2, CO2, steroids, small lipids)
39
Is the lipid bilayer permeable to water?
Yes
40
What types of molecules are impermeable to the lipid bilayer?
Polar and charged molecules, ions, and macromolecules
41
What do transmembrane proteins do?
Act as specific channels or carrier proteins
42
What types of molecules do transmembrane proteins transport?
* Small and medium-sized polar molecules * Charged molecules * Water and ions (e.g., Ca2+, Na+, Cl-)
43
What is the fluid mosaic model?
A sea of lipids in which proteins float like icebergs
44
What is the ratio of lipid molecules to protein molecules in the cell membrane?
50 lipid molecules to each protein molecule
45
What is passive transport?
Substances move from high concentration to low concentration through the plasma membrane
46
What is simple diffusion?
Movement from high concentration to low concentration directly through the membrane
47
What is facilitated diffusion?
Movement from high concentration to low concentration via a protein
48
What is the role of transmembrane proteins in facilitated diffusion?
Act as channels or carriers for substances
49
What is active transport?
Substances move from low concentration to high concentration via a protein and energy
50
What is the energy source for active transport?
Hydrolysis of ATP
51
What is vesicular transport?
Moves large bulky materials across membranes in small vesicles
52
What is the difference between endocytosis and exocytosis?
* Endocytosis: moves materials to the inside * Exocytosis: moves materials to the exterior
53
What are the six major functions of membrane proteins?
* Cell-Cell Recognition * Communication * Adherence * Defense * Connecting the membrane to the cytoskeleton * Signal Transduction
54
What are cell adhesion molecules (CAMs)?
Allow cells to adhere to each other via intercellular junctions
55
What is the role of the cytoskeleton?
* Aids cell movement * Confers cell shape * Maintains cell structural support * Aids in cell division * Organizes chemical reactions * Facilitates cell and organelle movement
56
What are microfilaments composed of?
Strands of the protein actin
57
What is the function of microtubules?
* Repositioning of organelles * Chromosomal movement during cell division * Movement of cilia and flagella
58
What is the structure of cilia and flagella?
Composed of microtubules
59
What is the nucleus?
Largest and most prominent organelle, main store for genetic information
60
What are the three regions of the nucleus?
* Nuclear envelope * Nucleoli * Chromatin
61
What is the nuclear envelope?
Double membrane that is continuous with RER and punctuated by nuclear pores
62
What is the function of the nucleolus?
Makes ribosomal subunits
63
What is chromatin composed of?
* 30% DNA * 60% Histone proteins * 10% RNA
64
What is the approximate length of DNA from one cell when stretched out?
2 meters
65
What are the components of chromatin?
* 30% DNA
* 60% Histone proteins
* 10% RNA
66
What is the Endomembrane System?
A system of membranous organelles that produce, store, and export biological molecules and degrade potentially harmful substances.
67
What are the two classes of the Endoplasmic Reticulum (ER)?
* Rough ER (RER)
* Smooth ER (SER)
68
What distinguishes Rough Endoplasmic Reticulum from Smooth Endoplasmic Reticulum?
Rough ER has ribosomes attached to its surface, giving it a 'studded' appearance, while Smooth ER has no ribosomes attached.
69
What are the functions of the Smooth Endoplasmic Reticulum (SER)?
* Synthesise phospholipids and cholesterol
* Synthesise steroid-based hormones
* Detoxify drugs
* Break down stored glycogen
70
What is the primary function of ribosomes?
Translate messenger RNA (mRNA) into proteins (amino acids).
71
What are polyribosomes or polysomes?
Multiple ribosomes attached to a single mRNA.
72
What are the functions of the Rough Endoplasmic Reticulum (RER)?
* Synthesis of soluble proteins used within the cell
* Synthesis of soluble proteins secreted from the cell
* Synthesis of many cell membrane proteins
73
What is the structure of the Golgi Apparatus?
A stack of 'pancake-like' membranous sacs with a 'receiving' face (cis face) and a 'transporting' face (trans face).
74
What happens to proteins in the Golgi Apparatus?
Proteins are modified and re-packaged prior to secretion from the cell.
75
What are lysosomes often referred to as?
The cell's 'demolition crew'.
76
What do lysosomes contain?
Powerful digestive enzymes.
77
What is the function of peroxisomes?
Contain powerful enzymes that detoxify harmful substances and neutralize dangerous free radicals.
78
What is the primary function of mitochondria?
Synthesis of Adenosine triphosphate (ATP), the cell energy source.
79
What does the endosymbiotic theory suggest about mitochondria?
Mitochondria contain their own DNA, RNA, and ribosomes, allowing for independent replication.
80
What are the two main processes that occur in mitochondria?
* Krebs Cycle (Citric Acid Cycle)
* Electron Transport Chain
81
Fill in the blank: The Endoplasmic Reticulum is a network of membranes closely associated with the _______.
[nucleus]
82
True or False: Smooth Endoplasmic Reticulum has ribosomes attached to its surface.
False
83
What metabolic activities do lysosomes perform?
* Breakdown of glycogen to glucose
* Breakdown of bone Ca2+ ions into bloodstream
