Unit 3 - Cellular Level Of Organization Flashcards
1
Q
The cell
A
- basic structural and functional unit of the body
- can perform all basic life functions
2
Q
Principal parts of the cell
A
- Cell membrane/plasma membrane/plasmalemma
- Cytoplasm (contains cytosol and organelles)
- Nucleus
3
Q
Cell membrane
A
Boundary between the inside and outside of a cell
4
Q
What is the cell membrane composed of
A
- Phospholipid bilayer
- Cholesterol
- Membrane proteins
- Membrane carbohydrates
- Microvilli
5
Q
Phospholipid bilayer
A
- Phosphate head group (hydrophilic) (polar)
- FA tails (hydrophobic) (non-polar)
- Divides ICF (intracellular fluid) and ECF (extracellular fluid)
- main component is water
6
Q
Cholesterol
A
- scattered throughout membrane
- adds stability to the cell membrane
7
Q
Integral (transport) membrane proteins
A
- can completely pass through membrane but doesn’t always
- integrated within the membrane, therefore have a hydrophobic region
- some extend across entire membrane, and are called transmembrane proteins
8
Q
Peripheral membrane proteins
A
- can face inside or outside of cell
- attached to either surface of integral proteins (on the periphery of the cell membrane)
9
Q
Functions of membrane proteins
A
- enzymes
- transporters (help transport molecules in and out of cell) (ATP is required)
- channels (ATP is not required)
- receptors (tell the cell what to do)
- anchors (needs to be anchored to a certain region of the body)
- identity markers (for immune system)
10
Q
Where are membrane carbohydrates found
A
Only on outer surfaces
11
Q
What are membrane carbohydrates bound to
A
Proteins (glycoproteins) or lipids (glycolipids)
12
Q
Function of membrane carbohydrates
A
- Cell recognition (spem recognizes egg)
- Anchor cells together
13
Q
What is microvilli
A
Small projections of cell membrane
14
Q
Function of microvilli
A
To increase surface area
15
Q
Where is microvilli found
A
- Kidneys
- increased surface area allows more waste to be absorbed - Small intestine
- increased surface area allows us to absorb more nutrients
16
Q
What makes up the fluid mosaic model of the cell membrane
A
- Phospholipid bilayer
- Membrane proteins
17
Q
Fluid mosaic model of cell membrane
A
- Fluid - membrane constitutions can move around (phospholipids and some proteins)
- Mosaic - proteins dot surface, like tiles in a mosaic
18
Q
What is cytoplasm
A
- area between the inside of the cell membrane and the outside of the nucleus
- consists of cytosol and organelles
19
Q
Cytosol
A
- gel-like intracellular fluid
- contains water, ions, and a suspension of carbohydrates, proteins and lipids
- may contain inclusions (ex. Melanin and glycogen)
20
Q
Organelles
A
- structures that preform a specific function and are essential for life
- can be:
1. Non-membranous- in direct contact with cytosol
2. Membranous- surrounded by membrane that isolates them from cytosol
21
Q
Cytoplasm analogy
A
Jelly cake
- cytosol = jello
- organelles = fruit
22
Q
Non-membranous organelles
A
- Ribosomes
- Centrosomes
- Cytoskeleton
23
Q
Ribosome function
A
- site for protein synthesis
24
Q
What do ribosomes contain
A
- ribosomal RNA (rRNA)
- proteins
25
Types of ribosomes
1. Free ribosomes
- float in cytosol and make proteins that go to cytosol, mitochondria, and/or nucleus
2. Attached to endoplasmic reticulum (ER)
- make proteins destined for all other sites
26
What are Centrosomes
Organizing centres for microtubules
1. Spindle apparatus (for cell division)
2. Organizes cytoskeleton
27
What do Centrosomes consist of
2 components:
- a pair of centrioles
- pericentriolar matrix
28
Function of cytoskeleton
- all types are used for structural support (cell shape) and are formed from proteins
- important in cell movement, cell division, movement/anchoring or organelles and proteins
29
Types of cytoskeleton
1. Microfiliaments
2. Intermediate filaments
3. Microtubules
30
What are microfilaments made of
Actin (protein)
31
Function of microfilaments
- muscle contraction (with myosin)
- cell locomotion
- cytokinesis (separating cytoplasm into 2 cells)
32
Composition of intermediate filaments
Tissue specific
- ex. Keratin (protein)
33
Microtubules
- hollow tubes made of tubulin (protein)
34
Function of microtubules
- Form:
1. centrioles
2. spindle apparatus
3. cilia (short)
4. flagella (long
- move or secure organelles in place
- also found in sperm
35
Membranous organelles
1. Mitochondria
2. Endoplasmic reticulum
3. Golgi apparatus/complex
4. Lysosomes
5. Nucleus
36
Mitochondria
- site of ATP synthesis
- has a double membrane (inner and outer)
37
What does the mitochondria contain
- DNA
- RNA
- Proteins
38
Endoplasmic reticulum
- membranous network throughout cytoplasm
39
Rough ER
- lysosomes attached
- synthesis of secretory, lysosomal and membrane proteins
40
Smooth ER
- lacks attached ribosomes
- continuous with rough ER
- synthesizes lipids and steroid hormones
41
Golgi apparatus/complex
- stacks of membrane discs
- modifies proteins (trims or adds carbs to lipids)
- sorts, packages and delivers proteins to cell membrane, lysosomes or for secretion
42
Golgi apparatus/complex analogy
Cellular post office
43
Lysosomes
- filled with digestive enzymes
- digest bacteria, viruses, worn out organelles
- clean up function
44
Lysosomes analogy
Lysol (cleans)
45
Nucleus
- largest membranous organelle
- cell control Center
- cells may have one or more nuclei
46
Parts of nucleus
1. Nuclear envelope
2. Nucleolus
3. Chromosomes/chromatid
47
Nuclear envelope
- covers nucleus
- double membrane with nuclear pores that information passes through (inner and outer)
- connected to ER
48
Nucleolus
- more than 1 in some plants
- inside nucleus
- non-membranous
- dense (less light gets through) region of DNA, RNA and proteins where ribosomes are made and assembled
49
What do Chromosomes/chromatid contain
- DNA
- Histone proteins
(DNA is wrapped around the histone protein)
50
Dispersed chromosomes/chromatid
= chromatin
- DNA uncoiled and not individually visible
- in this form MOST of the time (when cell is not dividing)
51
Where is condensed and individually visible chromosomes/chromatid found
In dividing cells
- during mitosis and meiosis
