Cells Undergo Chemical Reactions [3] Flashcards
What is metabolism
All chemical reactions that take place in a cell to keep it alive
Compare catabolism and anabolism and provide an example for each
Catabolism - molecules are broken down and release energy e.g. digestion
Anabolism - small molecules build up to form larger ones, consume energy e.g. protein synthesis
Define nutrients and its six groups
Substances used for growth, repair or maintenance
Water, carbohydrates, lipids, proteins, minerals, vitamins
What are organic compounds and examples
Molecules with a carbon chain
Carbohydrates, lipids, proteins, nucleic acids
Are carbohydrates organic or inorganic, and what elements make up carbs
Organic (contain carbon, hydrogen, oxygen)
What are the three levels of carbohydrates
Polysaccharides, disaccharides, monosaccharides
What are carbohydrates
Main source of energy for cells, simple sugars that are used in cellular respiration to release energy
What are monosaccharides and name 3 examples
“Simple sugars”, they are single-unit sugars.
Glucose, fructose, galactose
What are disaccharides and name 3 examples
Two simple sugars joined together
Sucrose, maltose, lactose
What are polysaccharides and name 3 examples
Chains of simple sugars joined together
Glycogen, cellulose, starch
What do complex carbohydrates do
Break down to simple sugars, which are broken down during cellular respiration for energy
What are lipids and their purpose
Fats made of glycerol and fatty acid chains (both including carbon, oxygen and hydrogen)
They are broken down so glycerol can enter glycolysis pathway and produce energy
What are proteins?
(composition, purpose)
100 or more layered amino acids, each protein is unique based on its amino acid structure
Contain carbon, hydrogen, oxygen and nitrogen
Used for tissue growth/repair, enzyme production
What is the composition of amino acids, and what do they do besides forming proteins?
How many amino acids are there?
Molecule that contains an amino group, and a carboxylic acid group
20 different amino acids
2 acids react to form a peptide bond and water molecule
Difference between polypeptides and dipeptides
Dipeptide - 2 amino acids joined
Polypeptide - >10 acids
What are nucleic acids
(chemical composition, structure, examples)
Large molecules with carbon, hydrogen, oxygen, phosphorous
Made up of nucleotides (nitrogen base, sugar, phosphate)
DNA and RNA
What are inorganic compounds and examples
Compounds not based on a carbon chain
Water, vitamins, minerals
Why is water important in metabolism
Dissolves other substances
Chemical reactions occur in water
What are minerals and its role in metabolism
Inorganic elements required by the body for development and function
Act as cofactors for enzymes, may be part of substances involved in metabolism (e.g. ATP)
What is are vitamins and their role in metabolism
Inorganic compounds acting as coenzymes for chemical reactions
What are enzymes?
PROTEINS that speed up chemical reactions (organic catalysts) by lowering activation energy
Allow body reactions to proceed at a sufficient rate
Work on substrates
Describe the lock and key model
(4 STEPS)
1) Enzyme joins with its complementary substrates
2) Form an enzyme-substrate complex
3) Complex breaks apart into one enzyme and 2 products
4) Enzyme shape remains the same and can be reused
What are factors of enzyme activity?
Amount of enzymes
Temperature
pH scale - each enzyme has its own optimal level
cofactors - some need extra molecules, e.g. vitamins, to change its shape
What is the optimal temp for enzyme activity and why?
30 - 40 °C, as a higher temp means deformed proteins and a lower temp means too slow
What is cellular respiration?
A metabolic process where organic molecules are broken down to provide energy for the cell
What are the organic molecules used in cellular respiration, and how are they formed?
Glucose - breakdown of complex sugars
Amino acids - breakdown of proteins
Fatty acids and glycerol - breakdown of lipids
Describe the structure of an ATP molecule and how it is formed
Adenosine ( 2 adenine and 1 sugar ribose ), and triphosphate ( 3 phosphate groups with high energy bonds )
Formed when a phosphate group is added to ADP
What is ATP and its purpose?
A molecule that transfers energy to where it is needed. Releases energy when the bonds between phosphate groups are broken
What is the chemical equation for cellular respiration, and what does it actually mean?
C⁶H²O + 6CO² —> 6CO² + 6H²O + energy
Is actually >20 steps, each catalysed by enzymes and releasing compounds and energy.
Describe glycolysis
Glycolysis (spitting glucose) occurs in cytosol.
1 glucose molecule breaks down into 2 pyruvate (pyruvic acid) and 2 ATP molecules.
No oxygen needed
Where does anaerobic respiration occur?
Cytosol
When does anaerobic respiration occur, and why?
No oxygen present, so it forms ATP by converting pyruvate into lactic acid. No ATP is produced.
What happens to lactic acid after anaerobic respiration
Converted back to glucose for aerobic respiration when oxygen is available
What happens during aerobic respiration?
What is required for it to happen?
Where does it take place?
Glucose completely breaks down into CO², H²O and ATP.
Oxygen is required
Mitochondria
How much ATP can one cycle of aerobic respiration can be produced
Up to 38
Name the steps in aerobic respiration (4 steps total)
Don’t describe
1) Glycolysis
2) Conversion of pyruvate into CoA
3) Krebs / Citric Acid Cycle
4) Electron Transport System
Summarise the products at each phase of aerobic respiration
(glycolysis, CoA conversion, Krebs cycle, electron transport system)
Glycolysis - 2 pyruvate, 2 ATP
CoA conversion - 2 acetyl Coa
Krebs cycle - 2 ATP and 2 CO²
Electron transport system - up to 34 ATP
34+2+2 = 38
What happens during pyruvate conversion
Pyruvate converted into acetyl coenzyme A (acetyl CoA) by removing CO2 and joining the remaining carbon atoms
What happens during Krebs cycle
Carbon atoms in acetyl CoA are released in CO2. For every acetyl CoA entering this cycle, 1 ATP is produced
What happens during electron transport system
Only phase that uses oxygen - electrons are passed between molecules, making oxygen molecules from water. Forms 26-34 ATP
Describe the types of energy produced in respiration and its uses
Chemical energy from glucose turns into:
60% heat energy (used for homeostasis)
40% chemical energy in ATP (used for many bodily functions, e.g. cell growth, movement, division, transport, nerve impulse transmission, etc)
