The Cell and its Contents Flashcards
(48 cards)
1
Q
Where do most diseases exert their effects?
A
Typically they exert their effects at a cellular level. Specifically on;
- cells of a tissue type
- cells of a single organ
- cells of an entire organ
2
Q
Label the diagram.
A
- Chromatin
- Nucleus
- Smooth Endoplasmic Reticulum
- Cytosol
- Lysosome
- Mitochondria
- Centrioles
- Centromere Matrix
- Microvilli
- Microfilament
- Microtubule
- Intermediate filaments
- Peroxidase
- Secretion being released from cell by exocytosis
- Golgi Apparatus
- Ribosomes
- Rough Endoplasmic Reticulum
- Plasma Membrane
- Nucleus
- Nuclear Envelope
(if rate based on 4 right answers = 1, 8 = 2, 12 = 3, 16 =4 & 20 = 5)
3
Q
What does the nucleus contain?
A
- Nucleoplasma or chromatin
- nucleolus
- nuclear membrane
- nuclear pores
4
Q
What is the difference between RNA and DNA? What are some of the nucleoproteins that are involved in both?
A
- Dexoyribose nucleic acid = DNA
- accounts for 20% of the mass of the nucleus
- contains the genetic material
- Ribose nucleic acid = RNA
- Is taken outside of the nucleus to produce functions
- is a complement of the DNA strand
- Histone proteins = binds to DNA and controls its coiling & thus, gene expression
- Non-histone enzymes
- for DNA and RNA synthesis
- regulatory proteins
*
5
Q
What is the nuclear Envelope?
A
- a two-layer unit membrane and intermembranous space
- outer lipid bilayer is continuous with the endoplasmic reticulum & has ribosomes over it
- Pore permit and regulate (active) exchange of metabolites, macromolecules and ribosomal subunits
6
Q
What are the two types of cells in the nucleus?
A
- Dividing cells
- Heterochromatin = electron-dense areas of tightly coiled inactive chromatin
- Euchromatin = pale staining areas is the part of the DNA used in the active synthesis of RNA
- Nucleolus = usually one but can have more in active cells & is the site of rRNA synthesis and ribosome assembly
*
7
Q
What are some of the cytoskeleton filaments?
A
- Microfilaments
- Intermediate filaments
- Thick filaments
- Microtubules
8
Q
What is a microfilament found? Describe it’s function and give an example of one.
A
- Present in the superficial zone of the cytoplasm
- is used in the cytoplasmic and membrane movement in endocytosis and exocytosis
- is in the microvilli of the intestines
- e.g. Actin
9
Q
What is the intermediate filament found? Describe it’s function and give an example of one.
A
- Is found in the cytoskeleton of the cells
- is a heterogeneous group in diameter
- supports and maintain asymmetric cell shape
- e.g. keratin in keratinocytes or glial filaments in astrocytes
10
Q
What is a thick filament found? Describe it’s function and give an example of one.
A
- Thick filaments are found in muscles but temporarily in other muscles
- Contraction of a muscle
- e.g. Myosin
11
Q
What is a Microtubule? Describe it’s function and what abnormalities may lead to.
A
- is composed of tubulin
- functions
- development and maintenance of cell form
- intracellular transport
- basic structure of some complex organelles
- e.g. centriols, cilia and spindle fibres
- Abnormalities in microtubules;
- lead to alteration in cell mobility and function
- Clinical use of colchicine in gout
12
Q
What is the plasma membrane made of?
A
- Phospholipid bilayer
- Smaller amounts of cholesterol and glycolipids
- Intrinsic (integral) proteins, mostly Transmembrane proteins
- Extrinsic proteins
- Pores = channels, which are formed by transmembrane proteins
13
Q
What is the function of the plasma membrane?
A
- Is a semipermeable membrane which separates intra and extracellular environments
- Cross-membrane transport through channels
- Cell-environment interactions through receptors
- electrical events = generation of AP
- regulates cell growth and proliferation
- Contains Glycocalyx;
- glycolipid and glycoprotein
- provides highly specific biological markers
14
Q
What is glycocalyx? What’s its function?
A
Glycocalyx;
- glycolipid and glycoprotein
- provides highly specific biological markers
15
Q
What is the cytosol?
A
Also known as the fluid matrix & is a colloidal solution of;
- water
- electrolytes
- suspended proteins
- neutral fats
- glycogen
- pigments e.g. melanin or bilirubin
16
Q
What is a ribosome? Where is it located and what is its function?
A
Ribosome
- nucleoprotein particles of rRNA and proteins
- is the site of protein synthesis
- has 2 globular subunits of unequal size & consists of;
- an rRNA strand
- associated ribosomal proteins
- together looks like a cottage loaf
- Location
- free (as ribosomes or polyribosomes)
- Attached to the endoplasmic reticulum = Rough ER
- Function
- free = synthesis of proteins used within the cell’s cytoplasm, nucleus and mitochondria
- Rough ER = synthesis of extracellular proteins e.g. digestive enzymes, hormones and neurotransmitters
17
Q
What does the Endoplasmic Reticulum consist of and what is its function? What is are the two types?
A
Endoplasmic Reticulum
- is a system of paired membranes with
- a matrix (fluid-filled space)
- cisternae (flattened sacs = storage)
- and vesicles connecting part to other parts of the inner cell
- Functions
- as tubular communication networks for transport of molecules through the cell
- has a large surface area & attached enzyme system = has an active role in cell metabolism
- Types
- Rough endoplasmic reticulum
- Smooth endoplasmic reticulum
18
Q
What is the rough endoplasmic reticulum made of? what is its function? Give an example of one of its functions.
A
Rough ER
- Is endoplasmic reticulum with ribosomes attached
- Function
- protein synthesis by ribosomes
- segregation from cytoplasmic components
- structural modification for specific function
- integral membrane protein synthesis
- first step in glycosylation
- example = makes;
- pancreatic digestive enzymes e.g. lipase
- liver plasma proteins e.g. albumin
- lysosomal enzymes (all cells)
19
Q
What is made of Smooth Endoplasmic Reticulum? What is its function? Give an example for one of its functions.
A
Smooth ER
- is ER with no ribosomes
- function
- synthesising enzymes for;
- lipid, lipoprotein and steroid synthesis
- regulation of intracellular calcium (in skeletal and cardiac muscle)
- Detoxification of lipid soluble drugs (in liver)
- Glycogen storage
- synthesising enzymes for;
20
Q
What is the Golgi Apparatus made of?
A
Made of stacks of four or more thin flat membranous sacs, located near the concave surface facing the nucleus
21
Q
What are the functions of the Golgi Apparatus?
A
- is associated with the ER
- modifies substances and packages into secretory vesicles
- which more into cytoplasm, fuse with cell membrane and then exocytose
- proteins are transported from the rough ER which then move to their allocated location in the lumen of coated vesicles or embedded within its membrane
- May produces larger carbohydrates (which can bind with proteins in RER to form glycoproteins)
- Helps with compartmentalization of the cell
22
Q
What are the 3 functional parts of the Golgi Apparatus? Where are they located (in relation to what)? What is each part specifically used for?
A
- Cis Face
- faces the nucleus
- receives transport vesicles from the smooth ER
- phosphorylates certain proteins
- is the “receiving” side
- Medial Golgi
- Adds sugar residuals to both lipids & peptides to form complex oligosaccharides
- Trans Golgi
- faces away from the nucleus
- performs proteolytic steps
- adds sugar residues
- sorts different macromolecules and directs them to correct vesicles
- is the “shipping” side
23
Q
Describe the shape of the mitochondria and what it is consists of.
A
Mitochondria (aka POWERHOUSE OF THE CELL)
- elongated cigar shape
- consists of;
- Outer membrane
- Cristae
- Matrix
24
Q
What is the function of the mitochondria?
A
- is involved in aerobic cellular respiration
- the matrix = is permeable with enzymes for lipid catabolism
- Cristae of inner membrane have;
- cytochrome which are the carrier molecules of the electrical transport chain
- enzymes for oxidative phosphorylation & ATP production
- Matrix = has enzymes for Krebs cycle or TCA cycle & fatty acid oxidation
- Are mobile, localise at sites of intracellular energy demand e.g. myofibrils
25
How does the Mitochondria differ to the other organelles?
* Variable number depending on the role of the cell = hepatocytes can 2000 mitochondria per cell
* Has its own circular DNA strands and ribosomes which synthesise 37 of their own constituent proteins
* can self replicate
* produces ATP
* cells that move a lot or are in areas that need lots of energy have lots of mitochondria
* In the production of ATP produces free radicals of O2 which is toxic to body = aging
26
What is a Mitochondrial Cytopathic Syndrome? How do they occur or arise? What dysfunction does it cause? How is it diagnosed?
1. Are the collective syndromes that are associated with dysfunction in the mitochondria.
2. the mitochondria is inherited from the mother (no paternal contribution as the spermatozoa are jettisoned at the point of fertilisation and penetrate the zona pellucida
3. Clinical patterns include
* abnormal mitochondrial DNA will impair the function of the mitochondria
* as genes for the 37 "mito" proteins are inherited from the mitochondrial DNA
* extracellular muscle weakness
* degenerative disease of the CNS
* metabolic disturbances = high levels of lactic acid
* Diagnosis is via
* Muscle biopsy and microscopic examination
27
What are lysosomes? What do they contain? Where are they made and what are the two types?
Lysosomes
* are membrane bound vesicles
* contain;
* 40 different acid hydrolases
* Proenzymes (for intracellular digestion)
* Types
* Primary
* Secondary
* Residual Bodies
28
What is the optimal pH of a lysosome?
The optimal pH is 5.0 because if the lysosome escapes into the cytoplasm it is less active at the higher cytoplasmic pH
29
Where are lysosomes synthesised?
The enzymes are synthesised in the RER and are packed into the vesicle in the Golgi Apperatus
30
When is a lysosome classified as a Primary (1o) lysosome?
when the enzymes have not yet begun digestive processess
31
When are lysosomes classified as a secondary (2o) lysosome?
* Also called a phagolysosome (endolysosome)
* when the 10 lysosomes fused with substrate material & the enzymes are activated
* chemical degradation process has begun
32
What are the ways secondary lysosomes degrade other cells?
Typically is either;
1. Autophagocytosis
* worn-out cells parts are recycled
2. Heterophagocytosis
* ingested bacteria in phagosome
33
When is a lysosome classified as a residual body?
When the secondary lysosomes contain undigested material.
e.g. Lipofuscin = age pigment in neurons, cardiac muscle) or carbon particles in lungs and tattoo pigments in macrophages
34
What is Autolysis?
is the release of enzymes into the cytoplasm = massive destruction of cell contents. (abnormal)
35
What cell acts on primary lysosomes & causes them to release? What occurs after this?
Neutrophils with bacteria act on the primary lysosome
Cause the release of the lysosomes contents into the extracellular spaces
Destroys surrounding cells e.g. purulent inflammatory lesions
36
What are lysosomal storage diseases?
* Are inherited
* is when a specific enzyme is absent or inactive,
* means that the digestion of cerebrosides, gangliosides or sphingomyelin does not occur
* e.g. Tay Sach's disease (autosomal recessive)
37
What are Peroxisomes?
Are membrane-bound organelles that contain specialised enzymes that degrades peroxides e.g. H2O2
38
What is the function of Peroxisomes?
Function in the;
* Control of free radicals = which are toxic
* catabolises very long chain fatty acids (C18 & above)
* formation of bile acids in liver cells
39
What do disorders in peroxisomes cause?
40
What organelles make up the intracellular membranous (endomembrane) system?
Endomembrane System
* Smooth ER
* Lysosome
* Nucleus
* Nuclear Envelope
* Rough ER
* Golgi Apparatus
* Vacuole
* Plasma membrane
* Transport Vesicle
41
Label the diagram
FLUID MOSAIC MODEL
14 answers
* 3 or less = 1
* 4 to 6 = 2
* 7 to 9 = 3
* 10 to 12 = 4
* 12 or more = 5
42
What are the functions of membrane proteins? (hint = 6)
1. Transport
2. Intracellular joining
3. Enzymatic activity
4. Cell to cell recognition
5. Receptor for signal transduction
6. Attachment to the cytoskeleton and extracellular matrix
43
What are the categories of transport across a cell membrane?
1. Passive Processes
2. Active Processes
3. Bulk Transport
44
What are the different types of passive transport?
45
What are the different types of active transport?
1. Primary Active Transport
2. Secondary Active Transport
46
What are the different types of Buk transport?
Also known as vesicular transport
1. Exocytosis
2. Endocytosis
3. Receptor-mediated endocytosis
47
What are some special membrane structures? What is their function?
1. Microvilli
* increase Surface Area = increase absorption
2. Membrane Junctions
* Tight
* Desmosomes
* Gap Junctions = communication tunnels which allow for the passage of small ions and molecules btw cells that are electrically active e.g. cardiac muscle cells
3. Cellular Extensions
* Cilia
* Flagella
* Both increase the motility of the cell or its ability to move substances over itself
48
