Biology Unit 1 Booklet 2 Cells, Cell transport, Cholera Flashcards
Convert cm to mm
X 10
Convert m to cm
X 100
Convert mm to micrometers
X 1000
Convert micrometers to nm
X 1000
Working out magnification
Magnification = measure scale bar in mm x conversion factor
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Number on scale bar
Working out actual size
Actual size = measure organelle in mm x conversion factor
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Magnification
Working out magnification without a scale bar
Magnification = measure organelle in mm x conversion factor
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Actual size in micrometers
Advantages of optical microscope
Small
Relatively mobile
View live specimen
Disadvantage of optical microscope
Poor resolution because light has a long wavelength
Two types if electron microscope
Transmission
Scanning
Transmission microscope
A beam if electrons through a sample so internal parts of the cell and organelles can be viewed
Produces 2D image in black and white called a micrograph
Scanning microscope
Send a beam of electrons which bounces off the surface of a molecule
Build up a 3D image of external surfaces
Advantage if electron microscope
Sorter wavelength therefore better resolution
Disadvantage of electron microscopes
Vacuum is expensive
Can’t view living things
Example of a Prokaryotic cell
Vibrio cholerae
An example if a eukaryotic cell
Epithelial cell
Prokaryotic cell
All bacteria possess a cell wall which is a mixture if sugars and peptide called…
This provides…
Peptidoglycan (murein)
A physical barrier against mechanical damage
Prokaryotic cell
Many bacteria also possess an external layer for further production
Capsule
Prokaryotic cell
Cholera bacteria also have a ______________ which rotates at its base and is used for moving through liquids
Flagellum
Prokaryotic cell
Inside the cell, what selectively controls the substances entering on leaving the cell?
Plasma membrane
Prokaryotic cell
Some Organelles are found dispersed in
Cytoplasm
Prokaryotic cells
The ___ S _________________ are where the cells proteins are made. These are found floating around freely in the cytoplasm
70
Ribosomes
Prokaryotic cells
The DNA of the bacterium is not not held within a membrane bound nucleus- the structure is known as
Nucleoid
Prokaryotic cell
The DNA is ___________ and does not form ___________________________________
Circular
Chromosomes associated with proteins
Prokaryotic cells
Many bacteria also contain smaller rings of DNA possessing important genes for the survival of the bacterium called…
E.g……….
Plasmid
Antibiotic resistance
Matrix is
Solution full of enzymes
Cristae is
Increased surface area for respiration
Stroma is
Liquid
Granum (stack of thylakoids)
Absorbs light for photosynthesis
Chlorophyll
What has ribosomes
Prokaryotes
Animal eukaryotes
Plant eukaryotes
What has rough endoplasmic reticulum
Animal eukaryotes
Plant eukaryotes
What has smooth endoplasmic reticulum
Animal eukaryotes
Plant eukaryotes
What has Golgi apparatus
Anima eukaryotes
Plant eukaryotes
What has a cytoplasm
Prokaryotes
Animal eukaryotes
Plant eukaryotes
What has a plasma membrane
Prokaryotes
Animal eukaryotes
Plant eukaryotes
What has a plasmodesma
Plant eukaryotes
What has a chloroplast
Plant eukaryotes
What has centrioles
Animal eukaryotes
Plant eukaryotes
What has a nucleoid
Prokaryotes
What has a nucleolus
Animal eukaryotes
Plant eukaryotes
What has plasmids
Prokaryotes
What has microvilli
Animal eukaryotes
What has a flagellum
Prokaryote
What has a capsule
Prokaryotes
What has mitochondria
Animal eukaryotes
Plant eukaryotes
What has a cell wall
Prokaryotes
Plant eukaryotes
What has lysosomes
Animal eukaryotes
Plant eukaryotes
Explain about ATP
Produced by mitochondria
During aerobic respiration
Mitochondria can be found in
Rib muscles
Heart
Brain
Muscles
ATP is needed for
Muscle contractions
Active transport
Nerve impulses
Fractionation happens in three steps
Homogenisation
Filtration
Ultracentrifugation
Why ice cold
Slows down enzymic activity of the lysosomes to prevent the broken lysosomes from digesting other organelles
Why isotonic
Prevents water entering or leaving the organelle by osmosis so that the organelle does not burst or shrink
Why buffer solution
Maintains a constant pH so that proteins within the organelle are not denatured and so the organelles do not lose their structure
Why homogenate
Remove cell debris
Heaviest to lightest organelles
Cell debris Nuclei Mitochondria Lysosomes Endoplasmic reticulum Ribosomes
What is a saturated fatty acid
There are no double bonds between carbon atoms in the hydrocarbon chain
Unsaturated fatty acids
Has double bonds between carbon atoms in the hydrocarbon chain
A triglyceride
A glycerol
3 fatty acids
A condensate reaction
Fluid mosaic model
Cell membrane structure
Protein molecule in a fluid bilayer of phospholipids
Bilayer is rigid
Fluid mosaic model
Why fluid
Semi liquid
Contain cholesterol
Fluid mosaic model
Why mosaic
Made of different molecules
Functions of membrane protein
Intercellular communications Transport Immune functions Structural purposes Enzymes Receptors (glycoproteins)
Lipids contain the element
Carbon
Hydrogen
Oxygen
Main role of lipids
Insulation
Internal organ protection
Buoyancy in some aquatic animals
Water proofing in some animals e.g. Bird feathers
Triglycerides are formed by the condensation of
Three fatty acids
On molecule of glycerol
Di glycerine
Two fatty acids
One fatty acid is replaced with a phosphate group
One molecule of glycerol
The bond that joins glycerol to a fatty acid
Ester bond
If there is a concentration difference, what will take place down the concentration gradient
Diffusion
Diffusion is
The net movement of particles from an area of high concentration to an area of low concentration across a selectively permeable membrane
What law applies to diffusion across any surface
Fick’s law
Diffusion transport does not need ATP therefore is
Passive
The only molecules that can diffuse passively are
Small
Non polar
Lipid soluble
Cells that are efficient at diffusion have
Large surface area to volume ratio
I.e. large surface area, small volume
The smaller the cell, the more efficient it will be because
Surface area to volume ration will be higher
The molecule that diffuse across the membrane by facilitated diffusion are
Large water soluble molecules like glucose and amino acids
Ions such as Na+, K+, Cl-
To get across hydrophobic zone in facilitated diffusion, what are used
Transmembrane proteins
Facilitated diffusion
The transmembrane protein can act as ____________ or _______________
Carriers-> big -> glucose
Channels -> small -> ions
Facilitated diffusion is ____________ it needs no energy
Passive
Facilitated diffusion down or against the concentration gradient?
Down
A cell may need to move molecules or ions across the membrane against a concentration gradient by
Active transport
Active transport only uses
Carrier proteins
Active transport needs energy from
ATP
In active transport, each protein is
Specific
Endo and exocytosis needs __________ to work
ATP
Endocytosis takes materials into the cell - how
The membrane folds in and engulfs the material
This creates a vesicle
Exocytosis works by
Vesicles formed inside the cell ( from the Golgi body) empty the contents to the outside
Pure water has.
A low water potential
Water potential is measured in
Kilo pascals (kPa)
Water can pass freely across the membrane but solute can’t therefore
Water will pass thought the membrane from a solution of high (less negative) water potential to a more negative
Osmosis is
The net movement of water from an area of less negative water potential to an area of more negative water potential across a selectively permeable membrane
Hypotonic red blood cell
Lynsey
Isotonic red blood cell
Normal
Hypertonic red blood cell
Shrivelled
Hypertonic plant cell
Plasmolyzed
Isotonic plant cell
Flaccid
Hypotonic plant cell
Turgid
Simple diffusion
Energy required?
No ATP
Simple diffusion
Direction of flow?
Down concentration gradient
Simple diffusion
Carrier protein / phospholipid / channel?
Phospholipids
Simple diffusion
Molecules?
Small, non polar, lipid soluble (CO2, O2)
Simple diffusion
How to speed it up?
Increase temperature
Increase surface area
Decrease diffusion pathway
Increase concentration gradient
Facilitated diffusion
Energy required?
No ATP
Facilitated diffusion
Direction of flow?
Down a concentration gradient
Facilitated diffusion
Carrier protein/ phospholipid / channel?
Carrier and channel protein
Facilitated diffusion
Molecules?
Amino acids
Glucose
Ions
Facilitated diffusion
How to speed it up?
Increase temperature to optimum Increase surface area Decrease diffusion pathway Increase concentration gradient Increase carrier protein number
Active transport
Energy required?
Needs ATP
Active transport
Direction if flow?
Against concentration gradient
Active transport
Carrier / phospholipid / channel?
Carrier protein
Active transport
Molecules?
Minerals, ions ( glucose, amino acids)
Active transport
How to speed it up?
Increase temperature to optimum Increase surface area Decrease diffusion pathway Increase concentration gradient Increase carrier protein number Increase mitochondria
Osmosis
Energy required?
No ATP
Osmosis
Direction of flow?
Down a concentration gradient
Osmosis
Carrier / phospholipid / channel?
Phospholipid
Osmosis
Molecules?
Water
Osmosis
How to speed it up?
Increase temperature
Increase surface area
Decrease diffusion pathway
Increase concentration gradient
Process of cholera infection
Bacterium anchors to small intestines epithelial cells using flagellum so it does not get flushed out
Secretes a protein by exocytosis, one part binds to a specific receptor (protein is complementary to the shake of the receptor )
Other protein ( exotoxins) binds and disrupts Cl- ion channel found in the epithelial cell membrane
Cl- ion diffuses from elks into the lumen ( passive, down gradient - low to high )
Water potential of lumen is more negative and water potential of cells are less negative
H2O moves from less to more negative water potential ( from cells to lumen )
Treatment for cholera
Oral rehydration therapy
Antibiotics
Vaccine
Rehydration solution contains
Sodium which encourages reabsorption if water
Glucose which stimulates uptake of sodium and provides energy
Potassium which stimulates appetite
Boiled water
