Unit 1: Chapter 3 Flashcards
Exergonic reactions
Release energy, more chemical energy in the reactants than the products
Endergonic reactions
Consume energy, more chemical energy in the products than the reactants
Requirements for life for a unicellular and multicellular organism
- access to a source of energy
- obtain organic molecules
- access water
- exchange gases
- remove waste products
To obtain energy organisms must be able to…
- capture energy from an external source
- convert this energy into chemical energy of organic molecules
- transfer energy produced in excess into organic molecules for storage
Types of energy
Thermal
Electrical
Radiant
Chemical
How do plants and algae capture energy?
By trapping radiant energy (sunlight)
How do animals and fungi capture energy?
Capture in the form of chemical energy from the organic molecules in their food
Is sunlight energy useful for cells? Why?
No, because sunlight is a diffuse form of energy that can be transported by cells or stored in that form in cells
How do plants change sunlight energy into chemical energy?
Photosynthesis
Word and chemical equation of photosynthesis
Carbon dioxide + Water > Glucose + Oxygen
6CO2 + 12H2O > C6H12O6 + 6O2
How does an animal break down their food?
Digestive enzymes produced by the animal break down the large organic molecules
In what form is energy stored?
ATP, glucose, glycogen (animals), starch (plants), fats and proteins
ATP
- Can be used immediately by cells
- Single step reaction
- Releases energy in small amounts
- Powers all energy-requiring reactions that keep all organisms alive
ATP reaction
ATP + Water > ADP + phosphate
When ATP combines with water it loses a phosphate through hydrolysis which releases energy and then the energy from glucose regenerates ATP to allow a phosphate to bond with ADP to make ATP
Glucose
C6H12O6
The chemical energy can be released and transferred to ATP
In cells, chemical energy of glucose is released by cellular respiration
1 molecule of glucose can produce 34-36 ATP
Glycogen
Polysaccharide in animals
Stored in liver and muscle
When needed glucose can be released from these energy stores
Excess glucose from food is stored as glycogen
Starch
Polysaccharide in plants
When needed glucose can be released to make energy
Fats
Tryglicerides stored in adipose tissue
Slower release energy stores
Largest in the human body
Energy in fats comes from fatty acids
Inorganic molecules
Water Oxygen Nitrogen Carbon dioxide Mineral quartz Iron ore hematite Aluminium ore bauxite
Organic molecules
Carbohydrates
Proteins
Lipids
Nucleic acids
Heterotrophs
Organisms that must obtain preformed organic molecules through feeding ie; animals
Autotrophs
Organisms that can make their own organic molecules from inorganic raw materials ie; plants
Different types of sunlight energy
High energy short wavelength ultraviolet radiation
to
lower energy infra red radiation
Chlorophyll
Allow plant cells to catch sunlight
Gives leaves their green colour
Embedded in the grana
Absorb sunlight best in blue to red peaks
Why are chloroplasts green?
Because the chloroplast does not absorb the light, it reflects it
Accessory pigments
Light capturing pigments
Carotenoids
Phycocyanin
Phycoerythrin
What light capturing pigments do plant cells contain?
Chlorophyll and carotenoids
Leaf structure components
Waxy cuticle Upper/lower epidermis Stroma guard cell Vascular bundle - phloem and xylem
Photosynthesis
Builds simple inorganic molecules (carbon dioxide and water) into complex organic molecules (glucose) that provide energy for living
Where are chlorophylls located?
On the grana membrane of chloroplasts
How many chloroplasts does a photosynthetic cell have?
40-200
Oxygenic photosynthesis
When oxygen is one of the products of photosynthesis
Leaves
- flat shape provides a large area to catch sunlight
- contains photosynthetic cells with chloroplast to catch light
- stomata on the underside of the leaf allow carbon dioxide to enter
- covered with a waxy cuticle
- internal air of the leaf allows diffusion of carbon dioxide
- vascular tissue contains xylem vessels and phloem tissue
Xylem vessels
In vascular tissue and transport water to photosynthetic cells
Phloem tissue
In vascular tissue to transport the products of photosynthesis from these cells to all other cells throughout a plant
Stems
- thick-walled xylem vessels give rigidity to stem
- branching of stems allows leaves to be positioned to catch more sunlight
- xylem vessels transport water and minerals from roots
- phloem tissue moves products to non-photosynthetic cells
Roots
- an extensive root system taps a significant volume of soil for water and mineral salts
- at the tip of the root, there are root hairs which have a large surface area for the absorption of water and minerals
Chemosynthetic autotrophs
Can build organic molecules from the oxidation of inorganic molecules from carbon dioxide
Aerobic respiration
Cellular respiration requiring oxygen
- Exergonic (energy releasing)
- C6H12O6 + 6O2 > 6CO2 +6H2O
- most energy released is lost as heat (60%)
- 40% efficiency
Anaerobic respiration
- anoxic (oxygen-free) environments
- called fermentation
- ATP is produced more rapidly
Step 1 of aerobic respiration (glycolosis)
- in cytosol of cell
- glycolosis - glucose breaks down into 2 molecules called pyruvate
- energy released produces 2 ATP
- pyruvate is transported into matrix of mitochondria
Step 2 of aerobic respiration (electron transport chain and krebs cycle)
- the inner membrane of mitochondria
- where oxygen comes so that 32 ATP can be produced
Rates of aerobic respiration
- different muscle tissues have different energy requirements
- measured by consumption of oxygen or uptake of glucose
Lactic acid fermentation
in skeletal muscles, after glucose is broken down into pyruvate an enzyme converts it to lactic acid
Phosphocreatine
Is in the skeletal muscles and can transfer its phosphate to produce ATP
ADP + PCr > ATP + Cr
Difference between aerobic and anaerobic respiration (fermentation)
oxygen not required for anaerobic
anaerobic had fast ATP production, aerobic is slower
anaerobic can be sustained for short time, aerobic for a long time
anaerobic is less efficient, aerobic is more
2 ATP made for anaerobic, 34-36 made for aerobic
end products; anaerobic can have lactate and water, aerobic has carbon dioxide and water
Factors that affect photosynthesis
Light
Carbon dioxide
Temperature
Water
Components of chloroplast
Outer membrane Inner membrane Thylakoid Grana Stroma
2 stages of photosynthesis
Light dependant Light independant ( calvin cycle)
Light dependent stage
water reacts with sunlight then NADP carries hydrogen to calvin cycle which produces Oxygen gas and NADPH+
located in grana or thylakoid membrane
Light independant stage
NADPH+ reacts with carbon dioxide to produce glucose and NAPD which goes back to the light-dependent stage
located in the stroma
Thylakoid
the individual membranes
Grana
a stack of thylakoids
Stroma
jelly like substance surrounding the grana
Plastid
energy converter organelle
Anaerobic respiration in animals
Glucose > Lactic acid + energy
C6H12O6 > 2C3H6O3 + ATP
Anaerobic respiration for plants ( fermentation)
Glucose > Ethanol + Carbon dioxide + Energy
C6H12O6 > 2C2H5OH + 2CO2 + ATP
Difference between chemosynthetic autotrophs and photosynthetic autotrophs
Chemosynthetic organisms do not require sunlight to create glucose for energy for survival, whereas photosynthetic organisms require light to produce glucose for energy
Inputs of photosynthesis
Light dependant - Water, NADP and sunlight has to be present
Light-independent - NADPH+, and carbon dioxide
Outputs of photosynthesis
Light dependant - Oxygen, ATP
Light-independent - Glucose, NADP
Where does the light-dependent stage occur
In the grana or thylakoid membrane
Where does the light independent stage occur
Stroma
Leaf structure
Cuticle
Upper epidermis
Mesophyll
Guard cells
How do gases leave and enter leaves?
Through the stomata
Waxy cuticle
Protects the leaf
Upper epidermis
Provides protection against pathogens
Mesophyll
Allows the leaf to photosynthesise
Guard cells
Open and close to moderate the process of respiration
Stoma
Opening on the underside of the leaf to allow gas exchange from photosynthesis
Inputs of glycolosis
Glucose
ADP + phosphate
Outputs of glycolosis
2 ATP
Pyruvate (C3H6O3)
Location of glycosis
Cytosol/cytoplasm
Inputs of aerobic respiration
Pyruvate
Oxygen
Outputs of aerobic respiration
32-34 ATP
CArbon dioxide
Water
Location of aerobic respiration
Mitochondria
End products of fermentation
Lactate and water
Ethanol and carbon dioxide
Butyl alcohol
Vinegar
