Enzymes, P/Synthesis, Cellular Respiration Flashcards
What are catalysts?
Catalysts are substances which speed up the rate of a chemical reaction, without using itself up
What is the substrate?
The substrate is the molecule that the enzyme acts on
How is the active site formed?
Formed by folding of polypeptide chains to form a small region with a unique shape
What happens if the shape of the active site is changed?
If the shape is altered by chemical or physical treatment the ability for the enzyme to function is reduced temporarily or permanently lost
What is it called when the active site is permanently changed?
Denatured
What is an enzyme with absolute or substrate specificity?
An enzyme can act on one substrate only
Eg.lactase
What is an enzyme with bond specificity?
An enzyme can only act on a particular type of chemical bond
Eg. Peptide bonds
What is an enzyme with group specificity?
An enzyme can only act on molecules with particular functional groups surrounding a bond
How are enzymes stopped from acting at inappropriate times?
Many exist as inactive pro enzymes (zymogens) which are only activated in response to relevant signals, this prevents them causing damage
What is monomeric enzyme?
Consists of a single polypeptide chain
What is an obligomer?
Consists of two or more polypeptide chains, these are called subunits. The subunits can either be different or identical
What is more common obligomer or monomeric enzymes?
Obligomer
What is metabolism?
The sum of all chemical reactions that take place in cells
What reactions breakdown?
Catabolic
What reactions build up?
Anabolic
What factors can effect the efficiency of enzymes?
Temp, pH, enzyme concentration, substrate concentration
What is a competitive inhibitor?
Some compounds resemble the substrate molecules and they compete for the same active site
What is rational drug design?
Biologists can work out the shape of many enzymes. They can design inhibitors that will stop certain enzymes from working.
Eg. Pain killers
What are non-competitive inhibitors?
Non- competitive or allosteric regulators bind to a site that is seperate form the active site. The inhibitor changes the shape of the enzyme meaning the substrate is unable to bind to the active site.
What are the inputs of p/s?
Carbon dioxide, water
What are the outputs of p/s?
Glucose (simple sugar), oxygen
What is a phototrophic organism?
Organisms that use sunlight to produce organic molecules eg. Sugar
What is autotrophic?
Turns simple compounds to organic compounds
What is an organic compound?
Carbon containing molecules
What is a producer?
Producers are organisms which have the ability to synthesise light for energy. Producer is another name for phototrophic organisms
What is p/s?
The process in which light energy is transformed into chemical energy stored in organic molecules such as sugars
Where does the light dependent phase occur?
The thylakoid membrane of a chloroplast
Where does the light independent phase occur?
In the stroma of a chloroplast
What comes first the light dependent or independent stage?
Dependent
Does the light dependent stage require light?
Yes
What are the two main actions that the electrons in the E.T.C do?
- pump H+ ions into the thylakoid space
- produce energy to form a new molecule NADPH
How are electrons that have been used in the E.T.C replaced?
From water
What is the process where water molecules are split called?
Photolysis
What does the process of photolysis produce?
Hydrogen, oxygen and electrons from the water
What energy source is used during photolysis?
Light energy
What is the waste product of photolysis?
Oxygen
What does ADP stand for?
Adenosine Diphosphate
What does ATP stand for?
Adenosine Triphosphate
What does Pi stand for?
Inorganic phosphate
What are stacks of thylakoid called?
Grana
Where is the higher concentration of chloroplasts?
Towards the surface as there is more sunlight penetration
What affects the rate of P/S?
- light intensity
- type of light (wave lengths)
- Carbon dioxide availability
- water availability
- temperature
What are the inputs of aerobic respiration?
Glucose and oxygen
What are the outputs of aerobic respiration?
Carbon dioxide, water and ATP
What is cellular respiration?
Cellular respiration is a catabolic energy yielding pathway. It is a process by which organisms breakdown energy rich molecules to be used to make ATP.
What are the major organelles used in cellular respiration?
Mitochondria and cytoplasm
Where does glycolysis occur?
Cell cytosol
Where does the transition reaction occur?
In the mitochondrial matrix
Where does the kreb cycle occur?
In the mitochondrial matrix
Where does E.T.C occur in cellular respiration?
In the mitochondrial cristae
What are the two main functions of glycolysis?
- Produce ATP and NADH
- produces pyruvate
What are the inputs of glycolysis?
Glucose
What are the outputs of glycolysis?
2 NADH, 2ATP, 2xPyruvate
What is the transition reaction?
Links pyruvate with the kreb cycle. The pyruvate is taken into the matrix and converted to Acetyl Coenzyme A (CoA)
What is the feed molecule of the Kreb cycle?
CoA
How many cycles is required for the Kreb cycle to completely breakdown a molecule of glucose?
Two
What does two turns of the Kreb cycle produce?
- 4 carbon dioxides
- 2 ATP
- 6 NADH + H+
- 2 FADH + H+
At what stage of cellular respiration is oxygen used?
E.T.C
What energy is used to power pumps on the membrane during E.T.C?
Energy from electrons carried by NADH +FADH
What do the proteins in the E.T.C pump?
H+ ions form one side of the membrane to the other
Where does the Calvin cycle occur?
In the stroma
What are the inputs of the light independent stage?
Carbon dioxide, NADPH, ATP, RuBP
How many turns of the Calvin cycle is required to synthesis a sugar molecule
2 turns
What is another name for the Calvin cycle?
Carbon fixation
What happens at the end of ETC?
Oxygen molecules pick up excess electrons to form water
What is the main purpose of P/S?
Convey radiant energy into chemical energy
What does fermentation of yeast produce?
Ethanol and carbon dioxide
What is anaerobic respiration?
Is a cellular process in which glucose is broken down in the absence of oxygen
What are the outputs of glycolysis in cellular respiration?
2ATP, 2NADH
What are the outputs of the Kreb cycle?
2ATP, 4 carbon dioxide, 6NADH, 2FADH
What are the outputs of ETC in cellular respiration?
32ATP, water
What is a cofactor?
A molecule which binds to the substrate in order to fit an active site
What is the waste product of anaerobic respiration in animal cells?
Lactic acid
What is the linking factor between P/S and cellular respiration?
Glucose
Metabolic reactions that release energy are said to be?
Exergonic
Metabolic reactions that require energy are said to be?
Endergonic
What are the two types of reversible inhibitors?
Competitive and non-competitive
How does rising temp affect the rate of reaction of enzymes?
For most chemical reactions an increase in temp causes an increase in reaction rate.
Why does the reaction rate increase when temp is higher?
Because the particles move faster and are more likely to collide with each other.
What happens to an enzyme once it’s on the too high side of their optimum temp?
On the other side of optimum is a range of temps at which enzymes will still operate but at a decreasing effectiveness till ultimate denaturing
What happens to enzymes if temps fall too low?
If temps fall too low the enzymes and substrates do not have sufficient energy to interact. Enzymes that have been inactivated due to low temps can be activated again once temp rises.
How do enzymes affect the rate of reaction?
Enzymes lower the energy level required and increase the reaction rate
What is another name for the Kreb cycle?
Citric Acid cycle
Does the Kreb cycle belong to p/s or cellular respiration?
Cellular respiration
Where would rubisco be expected to be found in high concentration?
Stroma
What is the role of oxygen as an output of the light dependent stage?
Released as a product
What is the role of ATP as an output of the light dependent stage?
Provides energy for the light independent stage
Are coenzymes organic or inorganic?
Organic
What is the role of NADPH as an output of the light dependent stage?
Supplies energy and hydrogen ions for the light independent reactions
Once NADH offloads it’s hydrogen and electrons it would
Collect more hydrogen from the breakdown of molecules in the Kreb cycle
What are the similarities between chloroplasts and free living prokaryotes?
- both have ribosomes
- circular DNA
- double membranes
During photosynthesis the splitting of water occurs when and where?
In the grana of the light dependent stage
Is the Kreb cycle apart of photosynthesis or cellular respiration?
Cellular respiration
Is the Calvin cycle apart of photosynthesis or cellular respiration?
Photosynthesis
Are anabolic reaction exergonic or endergonic?
Endergonic