energy, etc Flashcards
Bioenergetics is the flow-
energy through living systems
Life requires energy
Energy is transferred in living organisms via metabolic reactions
Metabolism is the total-
of all chemical reactions of the life process
Controlled by enzymes
Chemical reactions include forming, breaking, and re-arranging chemical bonds
Metabolic pathways are the
making or breaking of bonds
Anabolic pathways create bonds and build polymers
Consumes energy
Catabolic pathways break bonds and breaks down polymers to monomers
Releases energy
Thermodynamics is the study
energy and energy transfer
First Law of Thermodynamics
Energy can neither be created nor destroyed
Second Law of Thermodynamics
Energy in a system becomes less organized over time (entropy)
Energy input is required to maintain organization
Electro-Magnetic Energy
Light (visible spectrum & Non-visible (microwaves, uV, and infra-red)
Heat energy: is in the infra-red spectrum
Kinetic energy
Energy associated with work and motion of a system: sound & waves in the ocean
Potential energy
Stored energy in the system: compressed springs
Chemical energy
Potential energy stored in the atoms because of their positions in relation to other atoms (bonds)
Cells must
capture, store, and use energy to counteract the effects of the second law of thermodynamics
The reactions to maintain organization are not 100% efficient
Energy lost as heat
enzymes can
Enzymes speed up the reaction times by reducing the energy of activation
Enzymes control the speed and direction of the reaction
enzymes also
Enzymes binds to chemical reactants called substrates
Enzymes have highly specific locations, called active sites where the substrate binds.
metabolism and enzymes
Quantity of enzymes in a cell
Amount of energy
Inhibitors (competitive or noncompetitive)
Activators
Competitive inhibition is
when similarly shaped substrates can block the intended substrate from a enzyme
Some drugs and neurotoxins work this way
Allosteric molecules are commonly
Cofactors – inorganic ions such as iron, magnesium, and zinc
Coenzymes – organic molecules such as vitamins
Statins can
reduce cholesterol by inhibiting the enzyme that makes cholesterol from lipids in the body
Acetaminophen (Tylenol
inhibits cyclooxygenase
Cox inhibitors – fever and selling reducers
Metabolic or Biochemical pathways are
orderly sequences of chemical reactions, mostly catalyzed by enzymes
Biochemical pathways are composed of
ezymes that are components in the cells plasma membranes. (remember the endomembrane system)
Negative Feedback System
As the concentration of product increases the metabolic pathway is turned off
Use inhibitor molecules
Most common feedback system
Positive Feedback System
As the concentration of product increases the metabolic pathway is turned on
Use activator molecules
Least common feedback system
ATP is the source of energy for most metabolic pathways
Composed of adenine and ribose (adenosine) and three phosphate groups
One phosphate group is cleaved off to release energy (ADP)
Phosphate can be added on to store energy (ATP)
Cyclic
Cellular respiration
a catabolic pathway, uses chemical energy from food molecules to turn ADP back into ATP.
ATP turning into ADP provides the energy to do work for the organism
C6H12O6 + 6O2 → 6CO2 + H2O + Energy
Glucose + oxygen → carbon dioxide + water + ATP*
Photosynthesis occurs in two main stages
Light dependent reactions
Generate energy carriers ATP and NADPH
Light independent reactions
Create sugars via the Calvin Cycle
Pigments transfer the energy from the visible light spectrum
into usable energy for metabolic processes
There are primary and secondary pigments
Secondary pigments include:
Chlorophyll b, c, d, and e
Carotene a and b
Xanthophylls
Phycoerythrins
Phycoblins
Inside the chloroplasts are the thylakoid discs that
“capture” the visible light
They are studded with antenna complexes that are a combination of proteins and pigments.
Each complex can have a different combination of pigments
Light is used to break
water (H2O) which releases electrons into the 2 electron transport chain (ETC)
Products of ETS
Oxygen, 1 ATP, & 1 NADPH
Carbon dioxide fixation
utilizes carbon dioxide to produce carbohydrates
Photosynthesis – Light Independent Step 1
Carbon fixation by the enzyme RuBisCO
CO2 is attached to organic molecules (RuBP)
Photosynthesis – Light Independent step 2
Energy from light dependent reaction is used to create G3P (Glucose-3-Phosphate)
A Reduction Reaction
G3P is a three-carbon sugar
Used to remake RuBP and glucose
Photosynthesis – Light Independent step 3
RuBP is regenerated
It requires 6 turns of the Calvin cycle to make 1 glucose
Requires 36 ATP and 24 NADPH total
Calvin-cycle only plants are called
C3 plants
First product is a 3-carbon sugar
C4 and CAM plants have evolved
alternative forms of photosynthesis that create a 4-carbon sugar and reduce loss to photorespiration
Catabolism are Energy Releasing Reactions
Cellular Respiration
1)Glycolysis
2) Oxidation of Pyruvate
(Actyl Co- enzyme A)
3) Kreb’s Cycle (Citric Acid Cycle)
4) Electron Transport (ETS)
Energy consuming reaction-
Oxidative Phosphorylation
Photosynthesis is the process by
which light energy is used to make sugars from carbon dioxide and water; it generates oxygen gas as a by-product
Cellular respiration is the process
of releasing energy from food molecules to fuel cellular activities; it generates carbon dioxide and water as by-products.
Four main reactions of cellular respiration
Glycolysis
Oxidation of pyruvate
Citric acid cycle
Electron transport (ETS)
Anaerobic
An Nucleic acid is the H+ & electron acceptor
Aerobic
Oxygen is the final H+ & electron acceptor
Oxidation
the product Loses an electron
Reduction:
the product Gains an electron
Glycolysis
Enzyme-catalyzed reactions that break sugar molecules into pyruvates
Takes place in the cytoplasm, outside of the mitochondria
10 steps to glycolysis
Many are intermediate products
Requires 2 ATP to initiate (activation energy) & produces 4 ATP
Net +2 ATP
NADPH delivers energy by
providing electrons and hydrogen ions to anabolic pathways.
NADH picks up electrons and hydrogen ion
that have been released from catabolic pathways.
NADH and NADPH are the
electron acceptors in anaerobic reactions
2 pyruvates from glycolysis enter the mitochondria
to what?
Combine with coenzyme A (CoA) to create Acetyl CoA
Oxidation of Pyruvate
The primary substrate
2 Pyruvate molecules ( pyruvic acids)
All of the products
2 acetyl-CoA, 2 CO2, 2 NADH
Why is this reaction anaerobic?
NAD is the final electron acceptor
4. Note: this is the first of the phases to release CO2
Citric Acid Cycle
The primary substrate
2 Acetyl CoA
All of the products
4 CO2, 2 ATP, 6 NADH, 2 FADH2
Net energy
2 ATP
Why the reaction is anaerobic?
NAD and FAD are used as the final electron acceptors
Electron Transport Chain
It works via a proton gradient
Net energy is 32 ATP molecules
Why the reaction is aerobic?
Oxygen is the final electron acceptor
Oxygen is the final electron (H+) acceptor
Cellular Respiration Overview
The Equation
C6H12O6 + 6O2 → 6CO2 + H2O + Energy
CO2 comes from Citric Acid Cycle and Oxidation of Pyruvate
Water comes from Electron Transport System (ETS)
Energy comes from glycolysis (2), Citric Acid Cycle (2) and ETC (32)
Net Energy
Phosphorylation converts the energy from the reactions in cellular respiration into the average of 36 ATP molecules for all of cellular respiration
Fermentation
When oxygen isn’t available NAD+ still needs to be regenerated from NADH
Some organisms happily do this (archeans)
But usually a last resort to save itself for most organisms
Fermentation is one method to regenerate NAD
Alcohol Fermentation
Begins with glycolysis but no acetyl CoA formed
Key products: 2 ATP, 2 CO2, and 2 ethanol molecules
Lactic Fermentation
Occurs in your muscles when oxygen is running low
Key products: 2 ATP, and 2 lactic acid molecules
No CO2
Autotrophs
They can produce their own simple sugars from inorganic compounds
The biosphere
includes all the organisms on Earth, together with the physical environments in which they live.
Ecology is the scientific study
of interactions between organisms and their biotic (living) and abiotic (nonliving) environment.
A food chain
is a linear sequence of organisms through which nutrients and energy pass as one organism eats another;
Mineral Nutrient Cycles
Remember those 6 key mineral nutrients
1) Water
1a) Oxygen
2a) Hydrogen
3) Carbon
4) Nitrogen
5) Phosphorus
6) Sulfur
Water Cycle
Water is essential for all living processes.
The human body is more than one-half water and human cells are more than 70 percent water.
Land animals need a supply of fresh water to survive.
The water on Earth, 97.5 percent is salt water
Carbon Cycle
Carbon is the fourth most abundant element in living organisms.
Carbon is present in all organic molecules, and its role in the structure of biomolecules is of primary importance to living organisms.
The carbon based biomolecules make up 30% - 50% of the mass of an organism (Biomass)
Carbon compounds contain energy, and many of these compounds from plants and algae have remained stored as fossilized carbon (fossil fuels).
Nitrogen Cycle
Nitrogen enters the living world via free-living and symbiotic bacteria, which incorporate nitrogen into their macromolecules through nitrogen fixation into NOx (Nitrate & Nitrite) molecules.
NOx molecules are key to the formation of the amino acids and nucleic acids
Phosphorus Cycle
Phosphorus is often the limiting nutrient (necessary for growth) in aquatic, particularly freshwater, ecosystems.
Phosphorus is an essential nutrient for living processes; it is a major component of nucleic acids and phospholipids, and, as calcium phosphate, makes up the supportive components of our bones.
Phosphorus occurs in nature as the phosphate ion (PO4 ).
Sulfur Cycle
Sulfur is an essential element for the macromolecules of living things.
It is involved in the formation of proteins and nucleic acids
Atmospheric sulfur is found in the form of sulfur dioxide (SO2), which enters the atmosphere in three ways:
from the decomposition of organic molecules
from volcanic activity and geothermal vents
from the burning of fossil fuels by humans.
Climate
is defined as the prevailing weather conditions experienced in a region over relatively long periods of time.
The weather
is the conditions of the atmosphere in one area at a particular time.
Earth has six giant convection cells
in which warm, moist air rises and cool, dry air sinks, generating relatively consistent wind pattern
the Coriolis effect
Because of Earth’s rotation, winds appear to curve as they travel near Earth’s surface, a phenomenon known as
prevailing winds.
Winds usually blow from a consistent direction in a given location and are called
Biomes can
be categorized based on the unique climatic and ecological features of each such region.
Terrestrial biomes are
land biomes and are usually named after the dominant vegetation in the area.
Aquatic biomes
are found in water and are classified on the basis of physical and chemical features, such as salt content.
The Arctic tundra
covers nearly one-fourth of Earth’s land surface; it is frozen 10 months of the year and receives less precipitation than many of the world’s deserts.
Permafrost
permanently frozen soil found below the surface layers of the tundra.
The boreal forest
the largest terrestrial biome and includes the sub-Arctic landmass immediately south of the tundra.
Temperate deciduous forests
occur in regions with a distinct winter that lasts 4–5 months and precipitation that is distributed evenly through much of the year.
The grassland biome
found in both temperate and tropical latitudes.
The chaparral Biome
characterized by cool, rainy winters and hot, dry summers, and dominated by dense growths of scrub oak and other drought-resistant plants.
The desert biome
makes up one-third of Earth’s land surface and is defined by its lack of precipitation.
The tropical forest biome
characterized by warm temperatures and about 12 hours of daylight year-round.
Wetlands and estuaries
are often destroyed by humans to allow for development projects, while other aquatic biomes are negatively affected by pollution or erosion in the surrounding terrestrial environment.
Wetlands
characterized by standing water shallow enough that rooted plants emerge above the water surface.
Rivers and streams
are bodies of fresh water whose physical characteristics tend to change along their length and that move continuously in a single direction.
Lakes and ponds
are found in terrestrial landscapes and are therefore connected with abiotic and biotic factors influencing these terrestrial biomes. Lakes are defined as being greater than 5 acres
Marine biomes
are strongly influenced by climate, which helps determine factors like the temperature, depth, and salt content of the oceans.
An estuary
is a region where a river empties into the sea and is the shallowest of the marine ecosystems.
Salty water and fresh water mix daily
As a result, estuaries are some of the most productive ecosystems in the world.
The Intertidal Region
habitat to numerous types of small organisms. The intertidal zone is the region of land below water at high tides and above water at low tides. This region is also called the seashore and foreshore, and sometimes the littoral zone
The Neritic Zone
The neritic zone extends from the margin of the intertidal zone to depths of about 200 m (or 650 ft) at the edge of the continental shelf. When the water is relatively clear, photosynthesis can occur in the neritic zone. The water contains silt and is well-oxygenated, low in pressure, and stable in temperature. These factors all contribute to the neritic zone having the highest productivity and biodiversity of the ocean.
The Oceanic Zone
The Oceanic Zone is the open ocean . The oceanic zone has significant stratification.
What is a key role of NAD and FAD in cellular respiration?
To initiate enzyme activity
Cellular respiration produces carbon dioxide in which phases?
oxidation of pyruvate & Citric acid cycle
Enzymes control ________________.
The speed and direction of a metabolic reaction
When a biochemical pathways activity is increased as a concentration of product increases; the feedback system is:
positive
The primary pigment of photosynthesis is _____.
chlorophyll a
NADP and FADH functions in metabolism as ______.
H+ and electron carriers in the ETS systems
All of the chemical reactions of the life process are controlled by___.
enzymes
__________ covers several levels of the biological hierarchy: individual organisms, populations, communities, ecosystems, biomes, and the biosphere.
Ecology
A ________________is a concept that accounts for the multiple trophic (feeding) interactions between each species and the many species it may feed on, or that feed on it
Food Web
The carbon based biomolecules make up 30% - 50% of the ________ of an organism
Biomass
_____________ is defined as the prevailing weather conditions experienced in a region over relatively long periods of time.
Climate
_______________________ occur in regions with a distinct winter that lasts 4–5 months and precipitation that is distributed evenly through much of the year.
Temperate deciduous forests
The _________ is a region where a river empties into the sea and is the shallowest of the marine ecosystems.
estuary
Earth has 6 ___________ in which warm, moist air rises and cool, dry air sinks, generating relatively consistent wind patterns.
convection cells
