AS Flashcards
Compare transmission electron microscope and scanning electron
TEM>SEM higher resolution
TEM- shows the cells organelles and displays the cell interior
SEM- shows the surface and the 3D image
Describe how neutrophils,erythrocytes,squamous and ciliated epithelial cells is specialised
Neutrophils - many lysosomes,multi-lobed nucleus, for immune response, destroy pathogens
Erythrocytes- flattened disc,no nucleus, space for haemoglobin, flexible to squeeze through vessels
Squamous epithelium - flattened shape
very thin / (form layer) one cell thick, rapid diffusion
Ciliated
have cilia / ‘hair like’ structures which, move / beat
Waft mucus
Why do goblet cells contain mitochondria and Golgi apparatus
Required to produce ATP
to package protein
What is meant by the term esterification
Condensation reaction, loss of water molecule
Reaction between glycerol and fatty acids
What is meant by autoimmune disease
When the immune system stops recognising self cells/tissue starts destroying
What is the role of agglutination
Clumps pathogens together
Stops pathogens moving
Too big to enter cell
Outline the sequence of vaccination
Step 3- antigen binds to a specific B or T lymphocytes
Step 4- colonial proliferation
Step 5- t memory cells,stored in tissues, immunological memory cell, secondary immune response
What is the correct stage of mitosis
1- G2 2- Mitosis 3- cytokinesis 4- g1 5- S
Describe how a colorimeter is calibrated and why is it important to calibrate a colorimeter
Set to zero absorbency using blank distilled water
To ensure that everything is accurate and valid by measuring same standards
What do you find in a xylem tissue from a stem of a dicotyledonous plant
Vessel wall
Lumen
Pit
Name the covalent chemical bond labelled In the tertiary structure of the enzyme lysozyme
Disulphides
Alpha helix
Quaternary
Name the molecule that is found in the cells walls of bacterial cells
peptiglycagon
Suggest that type of chemical bind that lysozyme breaks and name the molecule other then the substrate that is needed for this reaction
Glycosidic
Water
Identify the type of phloem cell into which the stylet is inserted to obtain the sap.
Sieve tube
Explain why starch is not transported in the sap
Starch is insoluble therefore it doesn’t dissolve in water
Suggest why sucrose is a more suitable transport molecule than glucose
Unloading from source for sink
Less reactive and used up for aerobic respiration
Explain why it is important to use a differential stain when examining a blood smear under the microscope.
To see the difference between cells and organelles, contrast
Ensures WBC to be counted because they are transparent
Evaluate the scientist’s conclusion with reference to genetic biodiversity and species biodiversity.
genetic biodiversity:
genetic, diversity / variation, low / will decrease
small gene pool / few alleles (at each locus)
species biodiversity
wildcats may go extinct (in Scotland)
one less species correct ref. to species richness
correct ref. to species evenness
What is the term used to describe the difference between the two populations of a wildcat
Intra specific variation
Describe and explain the precautions that need to be taken when setting up and using the apparatus in Fig. 4.1 to ensure that no air is present.
setting up:
• D cut stem under water
• D have apparatus under water • D insert stem under water
• D joint(s) must be, sealed / tight
using:
• D do not allow the bubble to move too far
• D use syringe to move bubble
• E so air bubble does not enter, xylem / stem • E so same air bubble can be re-used
Describe the structure of the RER
And the role of the membrane
Molecules form a phospholipid bilayer, flattened sacs and covered in ribosomes,
Hold ribosomes in place
Barrier between organelle and cytoplasm for specific metabolic reaction
Explain how the nucleotides in a DNA molecule are arranged as two polynucleotide strands
Joined together by phosphodiester bond
2 hydrogen bonds between complementary bases AT
