Cellular Level Of Organization Flashcards
1
Q
What is the cell?
A
- basic structural and functional unit of the body
- can perform all basic life functions
2
Q
What are the principal parts of the cell?
A
- Cell Membrane/Plasma Membrane/Plasmalemma
- Cytoplasm
- Nucleus
3
Q
Cell Membrane/Plasma Membrane/Plasmalemma
A
- Boundary between the inside and outside of a cell.
- Composed of:
- Phospholipid belayer
- Cholesterol
- Membrane Proteins
- Membrane Carbohydrates
- Microvilli
1 & 3. Fluid Mosaic Model
4
Q
Phospholipid Bilayer
A
- phosphate head group (HYDROPHILIC -> loves water)
- FA tails (HYDROPHOBIC -> hates water)
- divides ICF and ECF
- Intracellular Fluid (ICF) = Inside cell
- Extracellular Fluid (ECF) = outside cell
5
Q
Cholesterol
A
- Scattered throughout membrane
- Adds stability to the cell membrane
6
Q
Membrane Proteins
A
- 2 types:
- integral protein
- peripheral protein
7
Q
What are the functions of membrane proteins?
A
- enzymes
- transporters
- channels
- receptors
- anchors
- identity markers (for immune system
8
Q
What is integral proteins?
A
- integrated within the membrane, therefore, have a hydrophobic region
- some extend across entire membrane, and are called transmembrane proteins
9
Q
What is peripheral proteins?
A
- attached to either surface of integral proteins I.e. on the periphery of the cell membrane
10
Q
Membrane Carbohydrate
A
- only on outer surface
- bound to protein (glycoproteins) or lipids (glycolipids)
- Function:
- cell recognition e.g. sperm recognize egg cell
- anchor cells together
11
Q
Microvilli
A
- small projections of cell membrane
- function is to increase surface area ( helps absorb nutrients)
- best seen on cells of the small intestine and kidney
12
Q
Fluid Mosaic Model of the Cell Membrane
A
- fluid = membrane constituents can move around (phospholipids and some proteins)
- Mosaic = proteins dot surface like tiles in a mosaic
13
Q
What is the Cytoplasm?
A
- AREA between the inside of the cell membrane and the outside of the nucleus
14
Q
What are the 2 divisions of Cytoplasm?
A
- Cytosol = gel-like intracellular fluid
- Organelles
15
Q
What is Cytosol?
A
- Contains water, ions, and a suspension of carbohydrates, proteins, and lipids
- May contain inclusions e.g. Melanin (pigment, glycogen (stored glucose)
16
Q
What is Organelles?
A
- Structures that perform a specific function and are essential for life
- are either:
- Non-membranous (in direct contact with cytosol)
- Membranous (surrounded by membrane that isolates them from cytosol)
17
Q
What are non -membranous organelles?
A
- Ribosomes
- Centrosomes
- Cytoskeleton
18
Q
Ribosomes
A
- Sites for protein synthesis
- Contains ribosomal (rRNA) and proteins
19
Q
What Two Types Can Ribosome Be?
A
- Free ribosomes - float in cytosol and make proteins that go to cytosol, mitochondria, and/or nucleus
- Attached to endoplasmic Reticulum (ER) - make proteins destined for all other sites
20
Q
Centrosomes
A
- Consist of 2 components: a pair of centrioles and the pericentriolar matrix
- Organizing centres for microtubules
- Spindle apparatus (for cell division)
- Organizes cytoskeleton
21
Q
Cytoskeleton
A
- All types are for structural support (for cell shape) and are formed from proteins
- important in cell movement, cell division, movement/anchoring of organelles and proteins (e.g. receptors, enzymes)
22
Q
What are the 3 types of Cytoskeleton?
A
- Microfilaments
- Intermediate Filaments
- Microtubules
23
Q
what is Microfilaments and it’s function?
A
- Made of actin
- Function: Muscle contraction (with myosin), cell locomotion and cytokinesis
24
Q
Intermediate Filaments
A
Composition is tissue specific
- e.g. Keratin
25
Q
what is Microtubules and it’s function?
A
- Hollow tubes made of tubulin
- Function:
- Form:
- Centrioles
- Spindle Apparatus
- Cilia (short)
- Flagella (long)
- Move or secure organelles in place
- Form:
26
Q
What are Membranous organelles?
A
- Mitochondria
- Endoplasmic Reticulum (ER)
- Golgi Apparatus/Complex
- Lysosomes
27
Q
Mitochondria
A
- Site of ATP synthesis
- Contains own DNA, RNA, and proteins
- have a double membrane
28
Q
Endoplasmic Reticulum (ER)
A
- Membranous network throughout cytoplasm
- 2 types:
- Rough ER (RER)
- Smooth ER (SER)
29
Q
Rough ER (RER)
A
- Ribosomes attached - synthesis of secretory, lysosomal and membrane proteins
30
Q
Smooth ER (SER)
A
- Lacks attached ribosomes
- Continuous with RER
- Synthesizes lipids and steroid hormones
31
Q
Golgi Apparatus/Complex
A
- Stacks of membrane discs
- modifies proteins (e.g. trims or adds carbs and lipids), sorts, packages, and delivers them to cell membrane, lysosomes, or for secretion (cellular post office))
32
Q
Lysosomes
A
- Filled with digestive enzymes
- Digest bacteria, viruses, worn-out organelles (clean up function)
33
Q
What is the Nucleus?
A
- Largest membranous organelle
- cell control centre
- cells may have 1 or more nuclei
34
Q
What are the 3 parts of the nucleus?
A
- nuclear envelope
- Nucleolus (>1 in some plants)
- Chromosomes/chromatids
35
Q
Nuclear Envelope
A
- Double membrane with nuclear pores
- Connected to ER
36
Q
Nucleolus (>1 in some plants)
A
- Non-membranous
- Dense (less light gets through) region of DNA, RNA, and proteins where ribosomes are made and assembled
37
Q
Chromosomes/Chromatids
A
- Contain DNA and histone proteins
- Can be:
- Dispersed = Chromatin
- DNA uncoiled and not individually visible
- In this form most of the time (when cell is not dividing)
- Condensed and individually visible
- Found in dividing cells (during mitosis/meiosis)
- Dispersed = Chromatin
