2.1.1 -- Cell structure [old shit] Flashcards
1
Q
How are Eukaryotic cells similar to Prokaryotic cells?
A
Both have a
- Plasma Membrane
- Cytoplasm
- Ribosomes for assembling amino acids into proteins
- DNA and RNA
2
Q
How are Eukaryotic cells different from prokaryotic? (1)
A
They are:
- Much Smaller
- Less well developed cytoskeleton and centrioles
- No Nucleus
- No membrane bound organelles such as mitochondria, endoplasmic reticulum, chloroplast, Golgi apparatus
- Wall made of peptidoglycan not cellulose
3
Q
How are Eukaryotic cells different from prokaryotic? (2)
A
Also have a
- Smaller Ribosomes
- Have Naked DNA that is not wound around histone proteins but floats free in the Cytoplasam as A loops (not linear chromosomes)
Also have:
- Protective waxy capsule surrounding their cell wall
- Small loops of DNA called plasmids, as well as the main loops of DNA
- Flagella - long ship like projections that enable them to move. (Structure different from prokaryotic undulipodia)
- pili - smaller hair like projection that enable backteria to adhere to host cells or to each
4
Q
What is an electron micrograph?
A
Photograph of an image seen using an electron microscope
5
Q
What is magnification?
A
Number of times larger an image appears, compared with the size of an object.
6
Q
What are organelles?
A
Small structures within cells, which have a specific function.
7
Q
What is a photomicrograph
A
A photograph of an image seen using an optical (light) microscope.
8
Q
Resolution
A
The clarity of an image, the higher the resolution the clearer thr image.
9
Q
What are the advantages of an Optical microscope
A
- Relatively Cheap
- Easy to use
- Portable, can be used in a field as well as Labs.
- Can study living organisms
10
Q
What are optical microscopes?
A
- Magnification up to x1500
- Resolution 0.2
3.
11
Q
What is the difference between Light interference and light absorption?
A
Light interference is used to produce a clear image without staining. Where as light absorption use staining
12
Q
Name the type of staining used
A
- Methylene is an all purpose stain
- Acetic orcein binds to DNA and stains chromosomes dark red
- Eosin stains Cytoplasm; Sudan red stains lipids
- Iodine in potassium solution stains cellulose yellow and startch granules blue/black (looks violet under the microscope)
13
Q
What is a Eukaroyric cell
A
Cell with an ultrastructure
- Nucleus surrounded by a double membrane called the nuclear envelope
- Has an area inside the nucleus called the Nucleolous which contains RNA, Chromosomes Unwind, making of ribosomes
- Jelly like cytoplasm in which organelles are suspended
- Cytoskeleton - network of protein filaments (actin or microtubules) within the Cytoplasam that moves organelles from one place to the of her. Allows some cells to move such as amoebae. Allows contraction of muscle cells
- Plasma membrane
- Small Vesicles
- Ribosomes (organelles without a membrane)
14
Q
Describe the structure of a nucleus.
A
- Surrounded by a double membrane called the nuclear envelope
- Nuclear envelope has pores in it
- Nucleolous (no membrane)
- Chromatin (genetic material) wound around histone protiens.
- When cell not dividing the chromatin is spread out or extended
- When dividing it condenses and coils tightly into chromosomes
15
Q
What is the function of the nucleus?
A
- Seperates content within the nucleus from the rest of the cell
- Some points of the nuclear envelope fuse together to allow some dissolved substances to diffuse through
- Allows large substances such as mRNA or steroid hormones to LEAVE the nucleus.
- Nucleolous, site of ribosomes production
- Chromosomes contain organisms gene
Control centre of the cell, stores genome, transmit genetic info, provides instructions for protein synthesis
16
Q
What is the structure of the ROUGH Endoplasmic reticulum?
A
- System of membranes containing fluid filled cavities called cisternaem, that is continuous with the nuclear envelope.
- Coated with ribosomes.
17
Q
What is the function of the ROUGH endoplasmkc recticulim
A
- Intracellular transport system, cisternae forms channels to transport material from one place of the cell to the other
- Large surface area for ribosomes
- Protiens actively pass through the membrane into the cisternae
- Transported to the golgi apparatus for modification and packaging.
18
Q
What is the function of a SMOOTH Endoplasmic Reticulum
A
- System of membranes with a fluid filled cavities called Cisternae that are continuous with the nuclear envelope
- Has no ribosomes
19
Q
What is the Function of the SMOOTH endoplasmic reticulum
A
- Contains enzymes that catalyse reactions involved with lipid metabolism such as:
- Synthesis of cholesterol
- Synthesis if lipds/phospholipds needed by the cell
- Synthesis of steroid hormones - Involved with absorption, synthesis ans transport of lipds (from the gut).
20
Q
What is the structure of the Golgi
A
- Consists of a stack of membrane-bound flatened sacs.
2. Secretory vesicles being materials to and from the Golgi apparatus
21
Q
What is the function of the Golgi Apparatus
A
- Modifies Protiens by
- Adding Sugar Molecules to make glycoproteins
- Adding lipid molecules to make lypoprotiens
- Being folded into their 3D shape. - Proteins packaged into vesicles then pinched off
- Either incorporated into the plasma membeane or exported out of the cell or stores in the cell
22
Q
What is the structure for the mitochondria (mitochondrion)
A
- Spherical, rodshaped, branched. (2-5um long)
- Surrounded by two membranes with a fluid filled space between them
- Inner membrane highly folded into cristae
- Inner PART of mitochondrion is a fluid filled matrix
23
Q
What is the function of the Mitrochindria
A
- Site of ATP (energy currency) production during aerobic respiration
- Self replicating, more can be made if the cell needs energy
- They are abundent in cells where much metabolic activities take place.
24
Q
What is a structure of a chloroplast?
A
- Large Organelles (4-10um)
- Only found in plants and some protoctsists
- Surrounded by a double membrane or envelope
- Inner membrane is continuous with stacks of flatened membrane bound stacks called thylkaoids (looks like a pile of plates) contains chlorophyll
- Each stack of thylakoids is called granum.
- Fluid filled matrix is called stroma
- Contains lips of DNA and starch grains
25
What is the function of the Chloroplast
1. Site of photosynthesis
- Stage 1: Light energy is trapped by chlorophyll, used to make ATP; it occues in the granum. Water splits to supply hydrogen ions
- Stage 2: Hydrogen reduced CO2, using energy from ATP, to make carbohydrates occuts in the stroma
2. Chloroplasts are abundant in leaf cells, particularly the palisade mesophyll layer
26
What is the structure of a Vacuole?
1. Vacuole is surrounded by a membrane called the tonoplast and it contains a fluid
27
What is the function of a Vacuole
1. Only plants cells have a large permanent Vacuole.
2. It is filled with water and solutes and maintains cells stability --> When full it pushes against the cell wall ---> making cell turgid
3. If all plant cells are turgid then this'll help support the plant, especially non woody plants.
28
What is the structure of lysosomes?
1. Small bags, formed in the Golgi apparatus, each surrounded by a single membrane
2. Contain powerful hydrolytic (digestive) enzymes
3. Abundant in phagocytic cells such as neutrophils and macrophages
4. Can ingest a pathogen such as a backteria
29
What is the function of a lysosome?
1. Keep the powerful hydrolytic enzymes separate from the rest of the cell.
2. Can engulf old cell organelles and forgiven matter, digest them and return the digested components to the cell to re use
30
What is the structure of the Undulipodia and Cilia
1. Extensions from the cell and are surrounded by the cell surface memvrane
2. Each contain microtubules
3. Formed from centrioles
31
What is the structure of a ribosomes?
1. Small spherical organelles about 20nm in diameter
2. Made of ribosomal RNA.
3. Made in the Nucleolous, as two separate subunits, which pass through the nuclear envelope into the cell cytoplasm and then combine
4. Some remain free in the Cytoplasam and some attatcg to the RER
32
What is the function of a ribosome
1. Ribsome bound to the exterior RER are mainly for synthesizing proteins that will be exported outside the cell.
2. Ribosomes that are free in the Cytoplasam, either singly or in clusters are primarily the site of proteinsynthesis to be used inside of the cell
33
What is the structure of a centrioles
1. Consists of two bundles of microtubules at right angles to each other.
2. athe microtubules are made of tubulin protein subunits
3. Arranged to form a cylinder
34
what is the function of the centrioles?
1. Vefore a cell divides the spindles (made of threads of tubulin) forms the centrioles.
2. Chromosomes attatcg to the middle part of thr spindle and motor protiens walk along the tubulin threads pulling the Chromosomes to opposite end
35
how is the centrioles involved in the formation of cilia and undulipodia?
1. before the cilia form the centrioles multiply and line up beneath the cell surface membrane
2. microtubules then sprout out words from each send through forming a cilium or undulipodium
centros I usually absent from cells open bracket higher close brackets plants but may be present in some unicellular green algae such as chlamydomonas
36
what is the structure of the cytoskeleton
1. Rod like microfilaments made of subunits of the protein actin
2. They are polymers of actin and each microfilament is about 7nm in diameter
3. Intermediate filaments about 10nm in diameter
4. Straight, cylindrical microtubules, made of protein subunits called tubulin 18-30mm diameter
5.
