Energy Reactions in Cells Flashcards
Define metabolism
The set of processes which derive energy and raw materials from food stuffs, and use them to support repair, growth and activity of the tissues of the body to sustain life.
Where does food go after it’s eaten?
GI tract
What is the overall purpose of food?
To supply the energy needs of the cell
What is food broken down into?
Nutrients
What happens once food has been broken down into nutrients in the GI tract?
They pass into the blood
What happens to food not absorbed into blood?
It is lost as faeces
What happens to the nutrients in the blood?
They are taken up by the tissues
What happens to nutrients in the tissue?
- Interconversion
- Storage (packaging nutrients into stores)
- Synthesis
- Utilisation
What happens to utilised nutrients in the tissues?
They can pass back into blood for transport
How can nutrients be used for energy?
They can be oxidised
What happens to any waste produced from the oxidation of nutrients?
It’s passed back into the blood, and then lost from the kidneys or lungs
How does biological chemistry occur?
In small, controlled, step-wise chemical changes
What are metabolic reactions organised into?
Metabolic pathways
Describe the nature of the metabolic pathways
Distinct but integrated
What allows for the interconnectivity of metabolism?
Staging points on pathways where nutrients can enter or leave
Do the metabolic pathways occur in all cells?
Some do, but some restricted to certain cell types, or compartments of cells
Give an example of a pathway that occurs in all cells
Glycolysis
What is which metabolic pathways occur in which cells related to?
Function
What do all pathways have?
- Start point
- End point
- Interconnections
- Intermediates
What are the intermediates in metabolic pathways known as?
Metabolites
What are the two main types of metabolic pathway?
NAME?
What do catabolic pathways do?
Break down larger molecules into smaller ones
What are smaller molecules produced in catabolic processes known as?
Intermediary metabolites
What do catabolic processes release?
Large amounts of free energy
How do catabolic processes release free energy?
Breaking chemical bonds
Are catabolic processes oxidative or reductive?
NAME?
What is meant by catabolic processes being oxidative?
They release H atoms- ‘reducing power’
What are the H atoms released by oxidative processes used for?
Can be used to fuel production of energy currency, or fuel biosynthesis in another pathway
What is the result of the metabolic steps being small?
Release small amounts of energy per step
What is the advantage of releasing small amounts of energy per step?
It can be captured for the future
What do we need catabolism for?
To allow synthesis within cells
What do anabolic processes do?
Synthesise larger cellular components from intermediary metabolites
What do anabolic processes need?
Energy in the form of ATP released from catabolism
Are anabolic processes oxidative or reductive?
NAME?
What is meant by anabolic processes being reductive?
They use H’s
Give the 4 products of catabolic metabolism
- Building block materials
- Organic precursors
- Biosynthetic reducing power
- Energy for cell function
Give 3 examples of building block materials
NAME?
What is meant by there being a dynamic state of cellular components?
There is interconversion between each other to meet cells needs
What are building block materials needed for?
- Cell growth
- Division
- Repair
Give an example of an organic precursor
Acetyl CoA
What is Acetyl CoA required for?
Interconversion of building block materials
Give two examples of molecules that capture biosynthetic reducing power
NAME?
What do molecules that capture biosynthetic reducing power do?
Capture H atoms
What is the energy content of fat?
37kJ/g
What is the energy content of carbohydrate?
17kJ/g
What is the energy content of protein?
16kJ/g
What is the energy content of alcohol?
29kJ/g
What is the basal metabolic rate for a 70kg man/ 58kg woman?
1700/1400kcal
What is meant by basal metabolic rate?
The energy required by an awake individual during physical, emotional and digestive rest at 18ºc by all the body tissues
How much energy is required for activity?
1000-3000kcal
How much energy is required for the specific dynamic action of food?
150kcal
What is the specific dynamic action of food?
The energy cost of ingestion, digestion and absorption of food- extracting molecules in a form that we can get into body
How long can we survive without food?
20-70 days, if given water