Chapter Three Flashcards
Cells undergo chemical reactions
What is metabolism
The total of all chemical process that occur in the body cells. These chemical process convert food into energy and materials needed for all life processes
Basal metabolic rate
The smallest amount of energy that can sustain life/keep the body functioning at rest
Inputs
- O2
- H2O
- Nutrients
Outputs
- CO2
- Metabolic wastes
- H2O
- Salts
Catabolism
- Metabolic process in which complex substances are broken down into simpler ones
- Releases energy
Cellular respiration equation
Glucose + Oxygen -> Water + Carbon Dioxide
(C6 H12 O6 + 6O2 -> 6H2O + 6CO2)
Anabolism
- Build up substances from simpler ones to complex ones
- Use energy
Protein synthesis
Proteins are made (synthesised) in the ribosomes, amino acids are linked into chains based on information from the DNA
How many common amino acids are there
20
Nutrients
- Any substance in food that is used for growth, repair or maintaining the body
- 6 groups > carbohydrates, lipids, proteins, minerals, vitamins and water
Organic compounds
Molecules with a carbon chain
(may contain H atoms and forms of O, N and S)
Carbohydrates
- Sugars and starches
- All contain 1C:2H:1O
- Smallest units are simple sugars
Another name for simple sugars is
Monosaccharides
Carbohydrate main uses
- Source of energy for cellular respiration
- Some combine with other substances
- Can be stored in the muscles and glucose
Sugars
- Relatively small carbohydrate molecules (monosaccharides or disaccharides)
- Water soluble and most are sweet
Monosaccharides
1 sugar molecule
- Glucose, galactose, fructose, ribose
Disaccharides
2 (double) sugar molecules
- Maltose, sucrose, lactose
Polysaccharides
7+ sugar molecules
- Glycogen, cellulose
Starch
- Long chains of simple sugars
- Not sweet
- Not water soluble
- Large part of carbohydrate intake
- Polymers
Polymer (def)
A substance with a molecular structure that had been built up chiefly or completely from a large number of smaller units bonded together
Lipids
- Fats and oils
- C, H + O elements w/ a smaller unit of O
- Smallest units are fatty acids and glycerol (some of which are essential)
Triglycerides
1 glycerol molecule attached to 3 fatty acid molecules
- Can be saturated or unsaturated (C + H bond)
Lipid (classification)
- Low density lipids carry cholesterol from the liver to the tissues > cholesterol inside LDLs are considered ‘bad’
- High density lipids collect cholesterol from the tissues and take it back to the liver > ‘good’ lipids
Lipids main uses
- Energy source > twice the energy of carbs
- Energy storage
- Insulation
- Protection of organs
- Structural Functions
- Metabolic Functions
Proteins
- Contains C, N, H + O
- Smallest units are called amino acids
- 20 different amino acids in the body
Dipeptide
2 amino acids bonded together by a peptide bond
Polypeptide
10 or more amino acids bonded together by peptide bonds
Proteins main uses
- Structural Functions
- Metabolic Functions
- Oxygen Transport
- Protection
- Energy source in emergencies
Essential amino acids
- The 8/9 that cannot be produced need to be obtained through the diet
- Complete proteins contain the full range of amino acids
- Incomplete proteins contain low levels of one or more essential amino acids
Nucleic acids
- Involved in the formation + function of a cells genetic information
- Smallest units are nucleotides
2 types of nucleic acids
DNA (2 chains of nucleotides)
RNA (1 single chain of nucleotides)
Inorganic compounds
- Not based on the carbon chain
- Water, Minerals, Vitamins
Water in metabolism
The fluid in which substances are dissolved
Minerals
A part of enzymes, cofactors of enzymes or part of the ATP
Vitamins
Coenzymes for many chemical reactions of metabolism
What is an enzyme
Proteins that allow chemical reactions to take place at normal body temperature by increasing the rate of reaction
- Act as catalysts
Catalyst (Def)
- Increase the rate of reaction
- Make it easier to react
- Do not get changed or used up in reactions
Activation Energy
- The energy required to start a chemical reaction
- Enzymes reduce the amount of energy needed
Lock and Key model
- Enzymes are each specific for only one substrate
- The enzyme and substrate both have a shape and structure that allows only them to fit together
- When locked together it is known as an enzyme-substrate complex
Induced fit model
- When the enzyme and substrate join they form weak bond that cause the shape of the enzyme to change complimenting the substrate
Anabolic enzyme action
- Helps build compounds in chemical reactions
- Requires energy
Catabolic enzyme action
- Breaks down compounds in chemical reactions
- Releases energy
Factors effecting enzyme action
- pH
- Temperature
- Concentration of enzymes + substrate
- Cofactors and coenzymes
- Inhibitors
Enzyme concentration
- The higher the enzyme concentration the faster the RoR
- By regulating the type and amount of enzymes present, the body is able to control which reaction occur and the rate in which they proceed
Substrate concentration
- Increases rate of reaction due to more substrate and enzyme molecules coming in contact
- Reaction increases until the point of saturation
Temperature
- Most enzymes work in a limited range of temp > too hot or too cold will reduce activity
- Because they are proteins their structure changes beyond 45-50C° and enzymes become denatured and inactive
pH
- Enzymes are sensitive to pH
- Altering pH can change shape of the active site and will alter its fit with the substrate
- All enzymes have an optimum pH at which they function best
Cofactors and coenzymes
- Many enzymes need the presence of certain ions or non protein molecules
- Change the shape of the active site
- Without cofactors enzymes cannot act
- Non-protein organic cofactors are called coenzymes (many of which are vitamins)
Inhibitors
- Substances that slow or stop an enzymes ability
- Used to control reactions
- Many drugs act as inhibitors
Where does the first step of cellular respiration occur
The cytoplasm
Where does the second step of cellular respiration occur
The mitochondria
Aerobic
With oxygen
Anaerobic
Without oxygen
Glycolysis
- Breaks down one molecule of glucose into 2 molecules of pyruvate acid (partial breakdown of glucose)
- Produces 2 molecules of ATP
- Takes place in cytoplasm
- Requires no oxygen
Krebs cycle
- Pyruvate acid is completely broken down into CO2 via enzymes
- Produces 2 ATP molecules
- Takes place in mitochondria
- Requires oxygen
Aerobic respiration
- The complete breakdown of glucose into carbon dioxide and water
- Requires oxygen
- Occurs in mitochondria
- Final process of respiration releases a large amount of ATP, 38 in total
- With O2 present the most energy is produced during this process
Anaerobic respiration
- Occurs when limited O2 is available and cells need energy
- Glycolysis -> 2 pyruvate molecules
- Occurs in cytoplasm
- Releases 2 ATP molecules
- If no O2 is available the pyruvate acid is converted into lactic acid
- No more ATP is produced
- Lactic acid build up in the muscles causes muscle pain and fatigue
Removing lactic acid
- Taken by the blood to the liver where it can be recombined with O2 to from glucose and eventually glycogen
- This process requires O2 therefore when respiring anaerobically our body builds up an oxygen debt
Oxygen debt symptom
- Heavy breathing is a symptom of oxygen debt and is needed to remove the lactic acid from the body by using extra oxygen (recovery oxygen)
ATP
Adenosine Triphosphate
ADP
Adenosine Diphosphate
Energy use of the cell
- Energy from the krebs cycle is used to convert ADP to ATP
- Energy is stored within the bond of the third phosphate, when removed (ATP-ADP) energy is released, when added (ADP-ATP) energy is stored
- Energy that goes into the ATP molecule comes from the food we eat
- Energy produced from ATP is used in cellular processes
Biological uses of energy
- 60/80% of this energy produced by the breakdown of ATP is heat energy > remaining heat is used for biological processes such as muscle contraction, synthesis or large molecules for growth and repair, cell diffusion + cellular activities such as moving substances into the cell
What is pyruvate converted in to
Acetyl CoA
Electron transport system
- Oxidative Phosphorylation
- Electrons are passed between molecules resulting in oxygen molecules forming in water
Product (Def)
A result of an action or process
Reactant
A substance that takes part in and undergoes change in a chemical reaction
Reaction rate
The speed in which a chemical reaction takes place
Synthesis
The production of chemical compounds through reactions of simpler ones
Protein synthesis
The process by which amino acids are organised linearly to produce proteins
Nutrient
A substance that provides nourishment essential for the maintenance of life and for growth
Active site
The active site is the part of the enzyme that combines with the substrate
Chemical concentration
An amount of substance in a certain amount of tissue or liquid
Denature
Destroy the chemical properties of
Inhibit
Hinder, restrain or prevent a process or action
Pathogen
A bacterium, virus or other microorganism that can cause a disease
Phospholipid
Other kinds of lipids that are important in the cell membrane, and steroids, including cholesterol and the sex hormones
Amino acid
A molecule that contains both an amino group and a carboxylic acid group
Electron transport system
Where electrons are passed between molecules finally resulting in oxygen molecules forming water
Cellular respiration
The process by which organic molecules are broken down in cells to release energy for cell activities
