2.1 Cell Structure Flashcards
Max magnification and resolution of a light telescope?
1500x and 200nm
What is used to stain DNA and which colour does it get stained?
Acetic orcein stains DNA dark red
What is used to stain bacterial cell walls and what colour do they appear when stained?
Gentian violet
What is needed to preserve the structure of cells in light microscopy?
The specimen is embedded in wax to preserve the structure of cells walls while cutting them into a thin slice
How do you correctly use a light microscope?
Calibrate the eyepiece graticule using the stage micrometer. This allows you to measure the size of the specimen.
What is the max magnification of an SEM?
Up to x100,000
What is the max magnification of a TEM?
Up to x500,000
Define magnification.
The degree to which the size of an image is larger than the object itself.
Define resolution.
The degree to which it is possible to distinguish two points of an object that are close together.
See detail
Descrive the organelles involved in protein synthesis?
- Made in ribosomes
- Ribosomes on RER make proteins that are excreted or attached to the cell membrane, cytoplasm stay in cytoplasm
- Processed and folded in RER
- Transported to Golgi apparatus in vesicles
- Golgi = further processing
- More vesicles and transported around the cell
What are plasmodesmata?
‘Channels’ for exchanging substances with adjacent cells
Function of cell membrane.
- Regulating movement of substances in and out of cell
- Receptor molecules which allow cell to respond to hormones
Function of lysosome.
- Contains digestive enzymes
- Digest invading cells
- Break down worn out components of the cell
Function of RER.
Folds and processes proteins that have been made by the ribosomes.
Function of SEM.
Synthesis of cholesterol
Synthesis of lipids and photo lipids
Synthesis of steroid hormones
Absorption and transport of lipids
Function of Golgi apparatus.
- Processes and packages new lipids and proteins.
- Makes lysosomes
What is the inner membrane of the mitochondria folded into?
Crista
What is the inside of a mitochondrion called and what is inside it?
The matrix and enzymes involved in respiration.
What is the inside of a chloroplast called?
Stroma
What is the pancake stack in a chloroplast called?
Granum
What is a granum a stack of?
Thylakoids
What joins thylakoids?
Llamella
What are centrioles and what are they used for?
Small, hollow cylinders made of microtubules. Found in animal cells, but only some plant cells. Involved in the separation of chromosomes during cell division.
What are cilia and what are they used for?
Hair-like structures found on some animal cells. Their cross section has a ring of nine pairs of protein microtubules with two in the middle, These allow the cilia to move or to move substances along the surface.
What are flagella?
Structured like cilia but longer. Contract to make the cell move.
How big a prokaryotic and eukaryotic cells?
Less than 2 micrometers and about 10-100 micrometers in diameter.
What is the cell wall of prokaryotes made of?
Polysaccharides, not cellulose (plants) or chitin (fungi)
Give examples of prokaryotes and eukaryotes.
E.coli bacterium and human liver cell
How do laser scanning confocal microscopes work?
Intense beams of light scan a specimen which is tagged with a fluorescent dye. This causes the dye to give off light which is then focussed onto a pinhole and through a detector. This is hooked up to a computer, which can produce a 3D image.
Max resolution and max magnification for all 3 telescopes.
light = 0.2 micrometers and x1500
TEM = 0.0002 micrometers and >x1 000 000
SEM=0.002 micrometers and <500 000
Order of use of light telescope.
- Clip slide
- Lowest objective lens
- Coarse adjustment knob
- Fine adjustment knob
Where is the eyepiece graticule?
Fitted onto the eyepiece, no units.
What is used to adjust the eyepiece graticule?
A stage micrometer.
How a protein threads arranged in eukaryotic cells?
Microfilaments and microtubules
What are microfilaments?
Small solid strands of protein threads.
What are microtubules?
Tiny protein cylinders.
How do you prevent microtubules and microfilaments from functioning?
By using respiratory inhibitors.
How big are prokaryotes?
Less than 2 micrometers.
How big are eukaryotes?
10-100 micrometers in diameter.
Difference in DNA in prokaryotes and eukaryotes.
Prokaryotes have circular DNA that is free in the cytoplasm. In eukaryotes, DNA is linear.
What is the cell wall of prokaryotes made from?
A polysaccharide - peptidogylcan.
What are eukaryotes cell wall made from?
Cellulose in plants or chitin in fungi.
What is the difference in the flagella of prokaryotes and eukaryotes?
In prokaryotes the flagella is made of flagellin and is arranged in a helix.
In eukaryotes flagella are made of microtubule proteins arranged in a 9+2 formation.
What is the difference in ribosomes in prokaryotes and eukaryotes?
Prokaryotes have small ribosomes while eukaryotes have large ones.
What is a photograph of the image using an optical telescope called?
A photomicrograph.
What is an all purpose stain?
Methylene blue
What stains cytoplasm?
Eosin.
What does eosin stain?
Cytoplasm.
What does Sudan red stain?
Lipids.
What stains lipids?
Sudan red.
What stains cellulose?
Iodine in potassium iodide stains it yellow
What stains starch granules?
Iodine in potassium iodide stains it black or blue.
What is the fancy name for starch grain?
Amylopast
What is the function of centrioles?
Cell division
Formation of cilia and undulipodia
How are proteins modified in the Golgi apparatus?
- adding sugar to make glycoproteins
- adding lipid molecules to make lipoproteins
- being folded into their 3D shape
What are protoctists?
Microscopic single celled organisms such as amoeba and chlorella.
What is the pathogen that causes malaria?
Pasmodiumis.
What is the membrane that surrounds the vacuole called?
The tonoplast
Where are lysosomes abundant?
In phagocytic cells such a neutrophils and macrophages.
Whag is an electron micrograph?
Photograph of an image seen using an electron microscope
Define organelles
Small structures within cells, each of which had a specific function
What is a photomicrograph?
Photograph of an image seen using an optical microscope
Pros of optical microscopes
Cheap
Easy to use
Portable
Living specimens
Describe TEM
Specimen dehydrated and stained
2D
What are thin slices of a specimen called?
Sections
Define eyepiece graticule
A measuring device in the eyepiece of a microscope and acts as a ruler
Define stage graticule.
A precise measuring device - small scale that is used to calibrate the value of eyepiece divisions at different magnifications
What happens in the nucleolus?
Ribosomes are made
How to ribosomes leave the nucleus?
Through areas where the inner and outer nuclear membranes fuse
What is the function of the nucleus?
Control centre
Stores genome
Transmits genetic info
Protein synthesis instructions
What are the cavities of the RER called?
Cisternae
Function of vacuole
Maintains cell stability
Features of lysosomes
Single membrane
Hydrolytic enzymes
Difference between flagella and undulopodia
Eukaryotes have undulipodia
Which organelles don’t have membranes
Ribosomes
Centrioles
Cytoskeleton
Cellulose cell wall
What are centrioles made of?
Two bundles of microtubules at right angles to each other
Made of Tubulin protein subunits
How are centrioles involved in the formation of cilia and undulipodia?
Centrioles multiply and line up beneath cell membrane
Microtubules spout out
Describe the structure of the cytoskeleton
Microfilaments Intermediate filaments Microtubules Motor proteins Myosins Kinesics
What are microfilaments made of?
Actin
Function of cytoskeleton
Support and mechanical strength Help substance and organelles to move through cytoplasm (Motor proteins) Form spindle Anchor nucleus Cell signalling to stabilise tissues
Function of cell wall
Strength and support
Maintain shape
Strength of whole plant
Permeable
Similarities between prokaryotes and Eukaryotae
Plasma membrane
Cytoplasm
Ribosomes
DNA RNA
Difference between prokaryotic and eukaryotic cells
Smaller Less developed cytoskeleton with no centrioles No membrane bound organelles Different cell wall Smaller ribosomes Naked DNA Binary fission
What is included in the structure of a chloroplast?
Double membrane Starch grain Granum Stroma Lipid droplet
Similarities between chloroplasts and mitochondria?
Double membrane DNA Lipid droplets Large internal surface area Ribosomes
What is Cristae
Inner membrane of mitochondria
Functions of proteins in plasma membrane
Attachment sites
Receptors
Enzymes
Transport
Define organ
More than on tho rod tissue working together to perform a function
Size of ribosomes in prokaryotes
18nm
Function of cytoskeleton from markscheme
Support cell Changes shape (eg cytokinesis) Moving organelles Holding organelles in place Make up centrioles and spindle fibres movement of cilia etc
Size of ribosomes in eukaryotes
22nm
Features of plant cells that are not features of animal cells
cellulose cell wall chloroplast amyloplast LARGE, PERMANENT vacuole tonoplast plasmodesmata
Feature of animal cell that is not present in plant cell
centriole
Why is staining good?
- Easier to see in more detail
- Increases contrast
- Recognise parts of the cell
- Identify different compounds/molecules
Is SEM 2D or 3D?
3D
How does vesicle move around?
Cytoskeleton provides pathways
Vesicles move along microfilamenrs/tubules
Microtubules broken down
Uses ATP
How to increase validity of experiment using microscope
sharp blade
thin slices - select thinnest
wet mount
squash slide
What is a brush border made of?
microvilli
Difference between cilia and microvilli
microvilli help in absorption whereas cilia help in rhythmic movement
Where are microvilli found?
small intestine, and increase the surface area for nutrient absorption.
Where are cilia found?
ciliated epithelial cells, like in the lungs
