Topic 1:3 - energy transformations Flashcards
define autotroph
primary producers and synthesise their own food from simple inorganic substances through the conversion of energy.
two types of autotrophs:
- Photoautotrophs, such as plants, phytoplankton and cyanobacteria, use light to produce glucose.
- Chemo-autotrophs, such as nitrogen-fixing and sulphur-oxidising bacteria, use inorganic molecules to produce organic molecules that can be used as food.
define heterotrophs
Heterotrophs consume autotrophs or eat other heterotrophs to obtain their food sources
Where is chlorophyll stored in eukaryotes vs prokaryotes
In eukaryotes, chlorophyll is stored in chloroplasts
In prokaryotes, chlorophyll is stored in thylakoid membranes near the cell membrane
photosynthesis equation
6CO2 + 6H20 -> C6H12O6 + 6CO2
(in presence of light and chlorophyll)
aerobic respiration equation
Most autotrophs and heterotrophs transform chemical energy for use through aerobic respiration:
glucose (C6H12O6) + oxygen (6O2) -> carbon dioxide (6CO2) + water (6H2O)
what is aerobic respiration
Aerobic respiration is the process of releasing energy through the complete breakdown of glucose molecules in the presence of oxygen.
It is a multi-stage process involving a series of highly organised chemical reactions, catalysed by specific enzymes. It results in the breakdown of glucose which released energy captured for production of ATP
three stages of aerobic respiration in eukaryotes:
- Glycolysis or non-aerobic steps in the cytoplasm resulting in pyruvate and only 2 ATP
2-3. Aerobic steps (Kreb’s cycle and Oxidative phosphorylation) in mitochondria.
How much energy is released during aerobic respiration?
The overall energy released in aerobic respiration is 36-38 ATP molecules
where does aerobic respiration occur in prokaryotes
the cytoplasm and cell membrane
what is anaerobic respiration?
Anaerobic respiration is the process of releasing energy through the incomplete breakdown of glucose molecules in the absence of oxygen.
the process of anaerobic respiration:
The process begins with glycolysis. The pyruvate produced remains in the cytoplasm and is converted into lactic acid in animals and or alcohol in plants and yeast.
How much energy is released during anaerobic respiration?
Anaerobic respiration releases energy that enables the production of only two ATP molecules.
aerobic respiration in animals and anaerobic bacteria results in:
lactic acid fermentation
equation for aerobic respiration in animals and anaerobic bacteria:
glucose (C6H12O6) -> lactic acid (2C3H6O3)
anaerobic respiration that occurs in plants and yeast results in:
Alcohol fermentation
the equation for: anaerobic respiration that occurs in plants and yeast
glucose (C6H12O6) -> ethanol + carbon dioxide (2C2H5OH + 2CO2)
define metabolic reactions
- The term metabolism is used to describe chemical reactions that maintain life processes in cells.
- All metabolic reactions involve changes in energy.
state whether DNA replication is anabolic or catabolic, give the reactant and product
Anabolic. DNA nucleotides (smaller) -> DNA (larger)
state whether Transcription is anabolic or catabolic, give the reactant and product
Anabolic. RNA nucleotides (smaller) -> mRNA (larger)
state whether translation is anabolic or catabolic, give the reactant and product
anabolic. Amino acids (smaller) -> polypeptide (larger)
state whether photosynthesis is anabolic or catabolic, give the reactant and product
anabolic. Carbon dioxide + water (smaller) -> glucose + starch (larger)
state whether oxidation is anabolic or catabolic, give the reactant and product
catabolic. hydrogen Peroxide (larger) -> oxygen and water (smaller)
state whether aerobic respiration is anabolic or catabolic, give the reactant and product
catabolic. glucose (larger) -> water and carbon dioxide (smaller)
state whether anaerobic respiration is anabolic or catabolic, give the reactant and product
catabolic. glucose (larger) -> lactate or ethanol, and carbon dioxide
state whether hydrolysis is anabolic or catabolic, give the reactant and product
catabolic. proteins/polysaccharides/lipids ATP breakdown (larger) -> amino acids/monosaccharides/glycerol and fatty acids
define ATP and describe properties/composition
Adenosine triphosphate (ATP) is a molecule used to store and release energy in all living things
composed of adenine (a base), ribose (the sugar found in RNA) and three phosphate groups.
ATP is small and water soluble which are properties required for efficient transport around the cytoplasm (80% water) of the cell.
ATP is synthesised from:
adenosine diphosphate (ADP) and inorganic phosphate (Pi).
ADP + Pi -> ATP
Describe the ATP cycle: catabolic and anabolic reactions
the synthesis of ATP from ADP and Pi is an anabolic reaction, which absorbs energy, storing is in the covalent bonds.
Energy is released in a catabolic reaction, where ATP breaks down into ADP and Pi. After this occurs, ATP is then reformed and the cycle continues
how should you answer a ‘use the information in the table and explain’ question
USE THE NUMBERS IN THE TABLE (and explain heheh)
explain three uses for ATP that result in the breakdown of ATP to ADP + Pi
- chemical work (e.g building a large molecule)
- mechanical work (e.g moving a muscle protein)
- transport work (e.g pumping solutes across a membrane)
Explain why glucose is broken down before ATP is produced. (2)
The energy within the glucose molecule is released (1) and used to synthesis ATP from ADP and Pi (1)
