Module 2 Flashcards
What are prokaryotic cells?
Single celled organisms that are small and simple
What are eukaryotic cells?
Complex and include all plant and animal cells
What is the function of the plasma membrane?
Regulates movements of substances in and out of the cell
What is the function of the cell wall?
Supports plant cells
What is the function of the nucleus?
Contains chromatin and the nucleolus
What is the function of the lysosomes?
Contains digestive enzymes to digest invading cells and break down worn out cell components
What is the function of ribosomes?
Making of proteins
What is the function of RER?
Folds and processes proteins
What is the function of SER?
Synthesises and processes lipids
What is the function of a vesicle?
Transports substances in and out of the cell and between organelles
What is the function of the Golgi apparatus?
Processes and packages new lipids, makes lysosomes
What is the function of the mitochondrion?
Contains enzymes for respiration, site of aerobic respiration
What is the function of the chloroplast?
Photosynthesis
What is the function of a centriole?
Used in the separation of chromosomes during cell division
What is the function of cilia?
Allow movement of substances along the cell membrane
What is the function of the flagellum?
Outboard motors that help the cell move
Process of protein production:
1 protein made at ribosome
2 RER ribosomes make proteins that are excreted or attached to the cell
3 free ribosomes make proteins that stay in the cytoplasm
4 new proteins are folded and processed at the RER
5 transported from the RER to Golgi Apparatus in vesicles
6 proteins are further processes and packaged by the Golgi
7 proteins enter more vesicles to be transported around the cell
8 IF being secreted the vesicle fuses with the plasma membrane and the protein leaves via exocytosis
What are microfillaments?
Small solid strands
What are Microtubules?
Tiny protein cylinders
4 main functions of the cytoskeleton
1 support the cells organelles, keeping them in positions
2 strengthen the cell and maintain its shape
3 responsible for movement of materials within the cell
4 proteins of the cytoskeleton can also cause the cell to move - cytoskeleton propels the cell eg flagellum
DNA in prokaryotes is…
Circular
DNA in eukaryotes is…
Linear
Prokaryotes are less than …. in diameter
2 micrometers
Eukaryotes are normally ….. in diameter
10-100 micrometers
Do prokaryotes have a nucleus?
No, dna is free in the cytoplasm
Do eukaryotes have a nucleus?
Yes, dna is inside the nucleus
Do prokaryotes have a cell wall?
Yes, but not chitin or cellulose
Do eukaryotes have a cell wall?
No cell wall, plant cells have a cellulose cell wall
Do prokaryotes have membrane bound organelles?
No, they have very few organelles and no membrane bound
Do eukaryotes have organelles?
Yes, they have many inc,using membrane bound organelles
What is the flagella made from in prokaryotes?
Flagellin, arranged in a helix
What is the flagella in eukaryotes made of?
Microtubule proteins in 9+2 formation
Prokaryotes have …. ribosomes
Small
Eukaryotes have ….. ribosomes
Large
An example of a prokaryote is….
E.Coli Bacterium
An example of a eukaryote is….
Human liver cell
What size are bacteria?
Roughly 1 10th of the size of a eukaryotic cell
Bacteria can be seen under a …. microscope
Electron
A bacterial cell contains what 6 things?
Flagellum DNA Plasma membrane Cell wall Plasmid Ribosomes
Define magnification
How much bigger the image is than the sample you are looking at
Define resolution
How detailed the image is - the ability to distinguish between two points that are close together
What is the formula for magnification?
Magnification = image / actual
What is the resolution and magnification of a light microscope ?
0.2 micrometers
X1500
What type of specimens can light microscopes look at?
Dead and Alive
How does a laser scanning confocal microscope work?
Uses laser beams to scan specimen that is tagged with a fluorescent dye
Laser causes the dye to fluoresce and give off light
Light is focused through a pinhole onto a detector, hooked up to a computer which produces an image - can be 3D
Any out of focus light is blocked = clearer image
How does a TEM work
Electromagnets to focus beams of electrons - transmitted through specimen
Denser parts absorb more electrons which make them darker on image
Provide high resolution images - organelles can be seen
How does SEM work
Scan beams of electrons across specimen
Knocks off electrons from specimen which is gathered in cathode tube to form an image
3D image
What is the magnification and resolution of a TEM
0.0002 micrometers
X1000000
What is the magnification and resolution of a SEM
0.002 micrometers
X500000
What stain is used with light microscopes?
Methylene blue or eosin
What does eosin stain?
Cell cytoplasm
What does methylene blue stain?
DNA
What are objects dipped in for electron microscopes?
Heavy metals such as lead, the metal ions then scatter electrons creating contrast
How do you prepare a dry mount?
Thin slice of specimen
Tweeters to place in middle of the slide
Tilt and lower the cover slip
How do you prepare a wet mount?
Pipette a small drop of water
Tweezers to place specimen in the middle
Tilt and lower the cover slip, avoiding air bubbles
Stain by placing a drop of stain on one side and place paper towel on opposite side
Stain will get drawn through
How to use a light microscope?
Clip slide to the stage
Lowest powered objective lens
Coarse adjustment knob to bring up stage to lens
Look down ocular lens and use coarse adjustment to focus on specimen
Adjust focus with fine adjustment knob until image is clear
Greater magnification = swap to a higher objective lens and refocus
An eyepiece graticule has …. units
No units
Stage micrometers have a …. scale
Accurate scale
What percentage of the cells contents is water
80%
What are the 5 functions of water?
Reactant Solvent Transport Temperature control Habitat
Water has a …. structure and can partake in ….. bonding
Simple and hydrogen
What are the 4 Properties of water?
High specific heat capacity
High latent of evaporation
Cohesive and good solvent
Less dense when a solid
What are all carbohydrates made of?
Carbon, hydrogen and oxygen
Glucose is what type of sugar?
Hexose , alpha and beta
Ribose is what type of sugar?
Pentode sugar, sugar component of RNA
What bonds join monosaccharides to form disaccharides and polysaccharides
?
Glycosidic bonds, using condensation reactions
How are these glycosidic bonds broken?
Hydrolysis
Examples of disaccharides
Maltose - two alpha glucose
Sucrose -alpha glucose and fructose
Lactose - alpha/beta glucose and galactose
Example of polysaccharides
Amylose - alpha glucose
What is Starch used for in plants?
Energy storage
Amylose
Long, unbranded chains of alpha glucose in coiled structure
Good for storage as more compact
Amylopectin
Long, unbranded chains of alpha glucose
side branches allow enzymes that break down the molecule = easy access
Glycogen
Main energy storage in animals
Alpha glucose
Side branches - released quickly
Compact - good for storage
Cellulose
Long unbranched chains of beta glucose
Straight cellulose chains
Linked together by hydrogen bonds - microbfibrils = structural support
Triglycerides
Macromolecules
One molecule of glycerol with 3 fatty acids
Contain Ester bonds
Saturated
No double bonds between carbons
Unsaturated
At least one double bond between carbons
Properties and functions of triglycerides
Long hydrocarbon tail - chemical energy released when broken down; twice as much as carbohydrate, insoluble
Properties and functions of phospholipids
Hydrophilic head and hydrophobic tail form double layer, water soluble substances can’t pass through easily - barrier
Properties and functions of cholesterol
Small size and flattened shape, fit between phospholipid molecules and bind to hydrophobic tails, membrane more rigid, less fluid
Proteins are …..
Polymers
Amino acids are …..
Monomers
Dipeptide
Two amino acids joined by peptide bond
Polypeptides are
More than two amino acids joined together
Amino acids contain…
Amino group, variable group, carboxyl group
Primary structure of proteins
Sequence of amino acids in a polypeptide
Peptide bonds
Secondary proteins
Hydrogen bonds form between near amino acids and coil into a alpha helix or beta pleated sheet
Hydrogen bonds
Tertiary structure
Coiled and folded further, more bonds form between parts of polypeptide chain, final 3D structure
Ionic bonds, disulphides bridges, hydrophobic/hydrophilic interactions, hydrogen bonds
Quarternary structure
Several different polypeptide chains held together by bonds, for proteins with more than 1 polypeptide chain
Bonds determined by tertiary bonds present
What happens if you heat a protein
Break up ionic and hydrogen bonds, change in 3D shape
Globular proteins
Hydrophilic R groups on outside of molecule, soluble, easily transported in fluids
Examples of globular proteins
Haemoglobin
Insulin
Amylase
Fibrous proteins
Insoluble and strong, structural and fairly unreactive
Examples of fibrous proteins
Collagen
Keratin
Elastin
Inorganic ions
Important in biological processes
Anions
Calcium Sodium Potassium Hydrogen Ammonium
Cations
Nitrate Hydrogencarbonate Chloride Phosphate Hydroxide
Benedicts test
Reducing sugars - all monosaccharides and some disaccharides
Add benedicts always use excess
Heat in water bath until boil
Precipitate brick red = positive
NON reducing sugars
Add dilute HCl and carefully heat, neutralise with sodium carbonate
Carry out benedicts
Test strips for glucose
Coated in reagent, compare to chart
Eg diabetes, infections etc
Iodine test for starch
Potassium iodide solution
Add to sample
Positive = blue black
Biuret test for proteins
Colours are pale so look carefully
Has to be alkaline so as NaOH
Add copper sulphate
Protein = purple
Emulsion test for lipids
Shake test solution with ethanol for 1 min
Pour solution into water
Milky if lipid present