5.7.1 The need for Cellular Respiration Flashcards
Why do organisms need energy?
Living organisms are composed of cells, and within each cell, many activities and processes are constantly being carried out to maintain life.
What are 4 essential types of work within organisms that require energy
- Transporting substances across membranes
- Anabolic reactions
- Movement
- Maintaining body temperature
Give an example of transporting substances across membranes using energy
Active transport using the sodium-potassium pump in cell membranes
Give an example of anabolic reactions using energy
Synthesis of protein from amino acids
Give an example of movement that requires energy
Cellular movement of chromosomes via the spindle
Give an example of maintaining body temperature using energy
Only occurs in mammals and birds
What is the source of energy and materials in organisms
The sun is the primary source of energy
How does the sun provide energy for organisms?
- Light energy from the sun is converted into chemical potential energy in the synthesis of carbohydrates.
- The carbohydrates formed are then used in the synthesis of ATP (from their breakdown) or are combined and modified to form all the usable organic molecules that are essential for all metabolic processes within the plant
- Photosynthesis is carried out by the first organism in a food chain, such as plants and some other small organisms
How does respiration release energy?
By breaking down organic molecules
It involves the transfer of chemical potential energy from nutrient molecules (such as carbs, fats, proteins) into a usable energy form (through the synthesis of ATP) that can be used for work within an organism
What is the respiration equation?
Glucose + oxygen -> carbon dioxide + water + energy
What are autotrophs?
Organisms that are able to synthesise their own usable carbon compounds from carbon dioxide in the atmosphere through photosynthesis
What are heterotrophs?
They dont have the ability that autotrophs do (cant synthesise their own usable carbon compounds) and so require a supply of pre made usable carbon compounds which they get from their food.
