Module 2 Flashcards
what does a TEM do?
electrons transmitted through specimen and focused to create a 2D image
what does an SEM do?
electrons sent across surface and reflected ones collected. lower resolution, but makes 3D images
what is an artefact?
a visible structural detail caused by processing of the specimen
where are ribosomes produced?
nucleolus
describe the structure of the mitochondria
double membrane, inner membrane is folded to form cristae, interior fluid called cristae. Has its own DNA
what does the cytoskeleton do?
maintains shape and stability of cell. Holds organelles in place, and causes movement of cell/organelle
what is the cytoskeleton made of?
Microfilaments for cell movement and cytokinesis,
Microtubules, can move organelles and creates spindle fibres
Intermediate fibres for mechanical strength
what arrangement do flagella and cilia have?
9+2 arrangement
what do cilia do?
Beat in a rhythmic manner to create a current to move things
what does SER do?
lipid and carbohydrate synthesis, and storage
what does RER do?
synthesis and transport of proteins, has ribosomes
where can you find ribosomes?
free in cytoplasm, on RER, in mitochondria, in chloroplasts
Describe the process of releasing proteins from the cell
proteins synthesized on RER
packaged into transport vesicles
move towards Golgi via vesicles
vesicles fuse with Golgi
proteins structurally modified by Golgi
proteins travel to cell surface membrane via vesicles
vesicles fuse with membrane and proteins released by exocytosis
what does the Golgi apparatus do?
modifying proteins and ‘packaging’ them into vesicles
describe cellulose cell wall function
gives shape, defense mechanism, and supports both cell and plant when membrane presses against it
what is the function of the vacuole?
generate turgor pressure
how is DNA stored in prokaryotes?
free, in one supercoiled chromosome
what are prokaryotic cell walls made of?
peptigoglycan
describe differences in ribosome sizes
eukaryotes have 80S, prokaryotes have 70S
which biological molecules contain nitrogen?
proteins and nucleic acids
what elements do lipids and carbohydrates contain
carbon, oxygen, hydrogen
what are polar molecules?
molecules with regions of negativity and positivity
describe the properties of water
High boiling point
ice is less dense than water, so floats
adhesion and cohesion
high specific heat capacity
describe how being a solvent makes water useful
acts as a medium for reactions, and can transport dissolved compounds
why is water a good transport medium?
due to capilliary action, and as it is a solvent
why is water being a coolant helpful?
because it can help maintain a constant temperature in an environment due to its high specific heat capacity, allowing enzyme controlled reactions to occur
why is water a good environment for fish to live in?
Because it is very stable. ice floats and creates an insulating layer to maintain stable temperature. the surface tension can also hold some insects
what is sucrose made of?
glucose and fructose
what is maltose made of ?
two alpha glucose
what is lactose made of?
galactose and glucose
what is starch made of?
amylose and amylopectin
describe the structure of amylose
many alpha glucose joined by 1-4 bonds, creating a helix which more is compact and less soluble than the glucose used to make it
describe the structure of amylopectin
mostly 1-4 bonds, but some 1-6 bonds that causes branching. this makes it very compact, and free ends mean glucose can be quickly added/removed.
is glycogen structurally similar to amylose or amylopectin
amylopectin, but with even more branches
how is cellulose formed?
with alternating alpha glucose molecules, creating a straight chain. cellulose is insoluble
how do you test for reducing sugars?
add sample and benedicts reagent
mix and heat in boiling water for 5 mins
should turn red
how to test for non reducing sugars?
boil sucrose(most common one) with HCl, will break down into fructose and glucose, both reducing sugars
how do you test for starch?
iodine solution will turn blue/black
why don’t lipids and water mix?
lipids are non polar
what are the bonds between glycerol and fatty acids called?
ester bonds
what’s the difference between saturated and unsaturated fats?
saturated have no carbon double bonds, whereas unsaturated have some, causing ‘kinks’. these mean they can’t pack as tightly, so are likely to be oils.
describe the structure of a phospholipid
charged phosphate head replaces a fatty acid chain.
what is a sterol?
a lipid that has a polar(hydrophilic) -OH group and the rest of the molecule is hydrophobic
list 8 lipid roles
membrane formation energy storage electrical insulation thermal insulation cushioning for vital organa hormone production waterproofing buoyancy
how do you test for lipids?
mix with water, then ethanol, and shake. look for white emulsion on the top
what is the bond between two amino acids called?
peptide bond
what is an amino acid chain called?
polypeptide
describe the primary structure of proteins
the sequence in which amino acids are joined
describe the secondary structure of proteins
hydrogen bonds may form within amino acid chain, pulling it into an alpha helix shape. they can also form a beta-pleated sheet.
describe the tertiary structure of proteins
the folding of proteins into its final shape
what interactions between R-groups can occur in the tertiary structure?
hydrophilic/phobic
hydrogen bonds
ionic bonds
disulfide bridges, only in cysteine
describe the quaternary structure of proteins
association of additional proteins called subunits
which R-groups will be on the inside/outside of proteins
hydrophilic ones will be on the outside and hydrophobic on the inside, because the are made in the aqueous cytosol
what is a globular protein?
a compact, water soluble protein that is roughly spherical.
what type of protein is insulin?
Globular protein. being water soluble helps it be transported in the blood
what is a conjugated protein?
a protein with a non protein prosthetic group.
what type of protein is hemoglobin?
conjugated protein
what type of protein is catalase (not enzyme)
conjugated protein
what are fibrous proteins?
long, insoluble molecules. They are very organized, and not folded
describe the structure of keratin
fibrous protein in hair, skin and nails. Has lots of cysteine, causing disulfide bridges. more disulfide bridges= tougher material
what is elastin?
fibrous protein found in blood vessels and alveoli. can freely stretch, and cause elastic recoil
what is collagen?
fibrous protein found in skin, tendons, ligaments and nervous system. used as a connective tissue.
what is a nucleotide made of?
pentose sugar
phosphate group
nitrogenous base