Bio Mocks Flashcards
What are the steps of PCR? What does it stand for and what is it for?
PCR stands for polymerase chain reaction and it is used to amplify a specific region of DNA.
Denaturation: 94-98 degrees Cel (Seperation of DNA strand) no enzymes used
Annealing: 50-65 degrees Cel (primers bind dna template) no enzymes used, only the attraction of the base pairs
Extension: at 74 degrees Cel, Taq polymerase adds nucleotides to the primers from 5’ to 3’, using the single stranded dna as a template.
What is the difference between methane and water?
Water has stronger, intermolecular bonds (hydrogen bonds) while methane has weaker intermolecular bonds (no hydrogen bonds). This means it takes less energy for to break methane’s bonds. Also, it has a lower melting, boiling, latent, and specific heat capacity.
What are carbohydrates made of? What are they?
carbon, hydrogen, and oxygen
Monosaccharides, disaccharides, and polysaccharides
What are some monosaccharides? Draw them.
fructose, Galactose,
Ribose and Glucose
glucose has two types: alpha and beta glucos
Ribose has 2 types: ribose and deoxyribose
What are and what are some disaccharides? What monomers are they made of? Draw them. (draw maltose from condensation and hydrolysis).
2 monosaccharides
Maltose (two alpha glucose)
Sucrose (glucose and fructose)
Lactose (glucose and galactose)
What are some polysaccharides?
2+ monosaccharides
Starch : how plants store their energy
- amylose (alphaglucose, alphahelical structure) (unbranched)
- amylopectin (alpha glucose, highly branched)
Glycogen: how animals store their energy
- highly branched alphaglucose polysaccharides
Cellulose: structural carbohydrates for plants
- beta glucose (linear). Alternating beta glucose
- each microfibril is connected to each other by hydrogen bonds, strengthening cellulose
What are lipids? Energy storage? their bond
Lipids are made of carbon, oxygen, and hydrogen. They are a more efficient energy storer than proteins and carbohydrates. They form ester bonds
What are some types of lipids?
triglycerides (usually for fat storage like adipose tissues)
Phospholipids (found in dna)
Steroids (hormones)
What are the types and structure of triglycerides
Triglycerides are made up of a glycerol head and 3 fatty acid chains. The chains are hydrocarbon chains. The triglyceride has some hydrogen bonds in it.
Unsaturated fatty acid chains:
- Cis: hydrogens on same side of double bond so that means that they have a kink (easier for permeability)
- Trans: hydrogen bonds on opposite
sides of the double bond so it is straight
Saturated fatty acid chains:
straight with no double bond
- Saturated fats can increase LDL cholesterol not HDL. Hence, it can increase cardiovascular diseases *
What does gene methylation do to gene expression in DNA?
This downregulates gene expression meaning it inhibits transcription.
Explain blood cells
These do not have a nucleus.
They also contain a protein called hemoglobins which attatch itself to oxygen, allowing blood cells to travel through the bloodstream (transportation).
They also have another protein called antigens on the cell membrane which communicate with white blood cells to protect it from pathogens.
Hence, antigens serve as a marker that white blood cells use to recognize your own blood cells so they don’t attack them.
How do you get different blood types?
You get 4 types from only two antigens ( A and B) because of 3 alleles.
- A allele codes for A antigens
- B allele codes for B antigens
- O allele codes for none
Now, since we inherit 1 allele from each parent (2 alleles in total), we get combination of 2 alleles that determine our blood type.
- O is recessive so others can overpower it
- AB are both prominent
- O blood type is universal donors
- AB are universal recipients
What is the light dependent reaction in photosynthesis
wavelengths of red have the highest while wavelengths of the violet has the shortest
Light dependent reaction happens within chloroplasts, between the lumen (instead of intermembrane space) and the stroma (instead of mitochondrial matrix).
The chlorophyll from Photosystem II (680nm) is excited making the electron excited. This leads to the electron to being passed down through the proteins until it reaches Photosystem I. As this happens, the electron loses its energy from the sun. The passing of this electron helps to push H+ across the membrane from the stroma to the lumen.
Photolysis breaks water and releases its oxygen out of the cell, the hydrogens add to the concentration in the lumen, and the electron released goes back to Photosystem II (680)
Then, the sunlight excites Photosystem I (700nm) where the electron passes through the proteins and leaves into the stroma. This is then used to reduce NADP to NADPH.
Later, the hydrogen iones go from the lumen down the ATP sythase where they pass down into the stroma. Then, adp is phosphorylated to atp.
What is the light inependent reaction of photosysnthesis?
Carbon Fixation:
This is a cycle where 3 molecules of CO2 from the stomata are combined with
RuBP from the enzyme, rubisco.
This produces 3, 6-carbon molecules that immediately break down into 6, 3-PGA .
Activation and reduction
Later, The PGA combines with 6 ATPs to make them energized making them called, 1-3 bisphosphoglycerate.
Then, the bisphosphoglycerate combines with NADPH to create 6 G3P.
Regeneration of RuBP
Theoretically, 1 G3P is half a glucose molecule. However, 5 of them have to combine with 3 ATP molecules and recreate RuBP for the Calvin cycle to happen again. This is why it’s inefficient.
Hence, the cycle has to happen twice in order to make one full glucose molecule.
What is osmolarity? Explain its impact on plant and animal cells
osmolarity is the measure of how much solute is in a solution
Hypotonic :
There is more solute concentration inside the cell than in the solution outside the cell–> animal cells swell and then lyse since they only have the cell membrane which isn’t strong enough to hold large amounts of water.
Plant cells become turgid (normal) becuase their central vacuole grows bigger but they don’t burst due to their cell wall which is strong as it has a straight and linear beta glucose structure that is held together by many hydrogen bonds.
Isotonic: this is when the solute inside of the cell and on the outside solvent is balanced.
–> animal cells become normal
–> plant cells become flaccid
Hypertonic: this is when the solute on the outside is more than the solute inside the cell. This causes the water to go out of of the cell (osmosis).
–> animal cells: shrivel
–> plant cells: plasmolyzed
What are the different types of diffusion
Facilitated diffusion: when there are ion channels where substances that have a charge or are too large can use to pass through. This goes with the gradient
Active diffusion: uses atp to go against the gradient
Passive diffusion: goes with the gradient and passes through the cell membrane on its own.
What are the reasons for the debate whether viruses are alive or not
Not alive:
Do not carry out metabolic processes
can not reproduce without a host
no response to stimuli
Alive:
can reproduce
contain genetic material
have complex structures such as proteins
can evolve / adapt to their environment
What are some differences between plant cells and animal cells?
They are both eukaryotic
Plant cells:
Chloroplast
central vacuole for turgidness and to hold water
cell wall for structure
Animal cells have centrioles
They both have mitochondria
Explain the Golgi apparatus
Found in both plant cells and animals cells
This has a cis face, closest to the ER, and a trans face which is farthest from the ER.
Golgi helps to package and make changes to the lipids, proteins, or carbohydrates made from the ER.
Golgi apparatus consists of cristae and lumen. The lumen contains special enzymes that help make the changes to the molecules. The molecules come to the Golgi through vesicles and go out through vesicles too.
The finalized molecules can either be shipped out of the cell or used inside for the membrane, etc.
Explain the Endoplasmic Reticulum
The ER can hold calcium
It has a RER
This part has ribosomes attatched to it. RER helps to process the proteins
SER
has no ribosomes but helps produce lipids, steroids, carbs
- can also process toxins and drugs
In muscle tissues, SER helps regulate calcium ions.
Explain the cytoskeleton
Gives the cell structure and mobility while keeping organelles in place
- Microtubules (25 nm)
These guys are made of alpha and beta tubulin dimers that form protofilaments. 13 protofilaments make one microtubule. Microtubules constantly rearrange themselves. They provide transportation for motor proteins and structure for the cell. They make up flagella and cilia of cells allowing for transportation with the motor proteins. - Intermediate filaments (10 nm):
These are the most stable filament of the cytoskeleton and they make up more stable structures such as hair. They provide structure for the cell while keeping organelles in place.
This is the primary structure of the cytoskeleton. - Microfilaments (7 nm):
shape of the cell and help with contracting muscle cells
made of actin proteins
double helical structure
What is the evidence that supports that eukaryotes came from prokaryotes?
- endosymbiotic theory:
Mitochondria and chloroplast have their own DNA
They have same size ribosomes as prokaryotes (70s)
They can reproduce on their own through binary fission
They have a double membrane
What is alcohol fermentation? Give a real life example.
Anaerobic respiration
This occurs in bacteria like yeast where the 2 pyruvates made from glycolysis get decarboxylated leaving 2 CO2 molecules as a byproduct. That turns them into 2 acetaldehydes which then loses two electrons and oxidizes 2NADH to 2NAD. Then, you are left with ethanol.
This process doesn’t produce ATP, it produces NAD which is important to regenerate NAD and continue glycolysis. A
In baking, yeast is combined with sugar to kickstart this process. The co2 from the decarboxylation of the pyruvates are what produces the air bubbles that make yeast and bread rise (soft). Later, the ethanol is baked off due to their low boiling temperature.
What is lactic acid fermentation?
This is used in humans when there is no oxygen (anaerobic respiration).
This goes from the 2 pyruvates that get reduced as 2 NADH molecules turn into 2 NAD molecules. This produces lactic acid.
overreliance on lactic acid fermentation can lead to lactic acid buildup where enzymes can’t function properly due to a change in the pH levels. Hence, this causes fatigue in muscle cells.
What is the linked reaction?
If there is oxygen, the 2 pyruvates can enter into the mitochondria and perform a linked reaction. Here, a pyruvate decarboxylases which reduces NAD to NADH. This 2 carbon molecule gets add to co enzyme A which will finally make acetyl CoA.
What are some similarities and differences between DNA replication and DNA transcription?
Both use polymerases
DNA replication uses DNA polymerase I and III
Both use DNA as a template
DNA replication uses both strands while transcription uses one
RNA transcription uses mRNA and leaves the nucleus thus necessitating poly a tails for security and to prevent the degredation of mRNA.
DNA replication is semi conservative.
Difference between microscopes?
SEM is an electron microscope that comes out in black and white but can get a close up of the actual cell, only the outside of it.
TEM is an electron microscope that is black and white and can see the details of the inside of a cell.
Light microscopes come out in colors.
What are the stop codons for translation
U Are Annoying (UUA)
U Go Away (UGA)
U Are Gone (UAG)
What is the formula for magnification
Actual size = size of image on screen / magnification
