KSU Bio 198 Exam 5

Describe the First and Second Laws of Thermodynamics and explain why they are important to the cellular energetics.

1st - energy cannot be created or destroyed, only change forms.

• This is important because all living things need a constant energy source (the sun)

2nd - when transforming energy, some is lost as heat (10% between trophic levels)

Define endergonic and exergonic reactions and describe how they are linked in cellular energetics.

Endergonic - requires energy (hydrolysis; splitting molecules)

Exergonic - releases energy (condensation; putting molecules together)

Describe the basic structure of ATP, understand how it stores and releases cellular energy (i.e. its role as an energy carrier), and the relationship of ATP to exergonic and endergonic reactions.

ATP is the energy carrier of cells. It powers cell actions. short term usable energy

Adenine, ribose (5-carbon sugar) and 3 phosphate groups

ATP loses a phosphate group (exergonic) which creates ADP

ADP gains a phosphate group (endergonic) which created ATP

Describe oxidation and reduction reactions and explain their relationship to endergonic and exergonic reactions.

Oxidation - electrons are REMOVED from substances when breaking molecules (endergonic)

Reduction - electrons are ADDED. molecules are synthesized. (exergonic)

Oxidation and reduction ALWAYS happen together (redox reactions)

Describe the process of diffusion and the factors that influence diffusion rates.

Diffusion - moving from high concentration to low concentration

- small non-polar molecules diffuse best (carbon dioxide, oxygen)

- CAN occur across membranes

Describe selective permeability and how it influences movement of materials across plasma membranes, including what types of molecules easily pass through the membrane and what cannot.

Selective permeability - allows some things to pass through, but not all. Membrane is asymmetric (inside and outside are different). Only non-polar molecules can pass through because the plasma membrane is polar (their charges are repelled)

Describe facilitated diffusion and active transport, the differences between them, and when the cell might use each transport type.

facilitated diffusion - materials diffuse across plasma membrane with help from membrane bound proteins; uses glucose, amino acids, and ions.

Proteins shield polar molecules from repulsive forces of membrane, allowing for diffusion

Material that needs transported first attaches to the protein or glycoprotein

HIGH to LOW concentration, needs a concentration gradient and carrier molecule.

Active transport - moving from LOW to HIGH concentration. requires energy and carrier molecules. uses sodium, potassium, and sugars.

Describe the process of osmosis and explain how solute concentration differences across a membrane influence osmotic movement.

Osmosis - the diffusion of water across a selectively permeable membrane

Hypertonic - extracellular fluid has a higher osmolarity (concentration) than the

fluid in the cell. Causing the water to move out to dull the extracellular fluid. The cell will shrivel up as a result and could possibly become destroyed as a result

Isotonic - the concentration of the solute is the same inside and outside of the

cell. There is an even amount of water moving in and out of the cell, so the size remains the same

Hypotonic - the extracellular fluid has a lower osmolarity (concentration) than the cell's cytoplasm. Water will move into the cell. Could get so big it gets destroyed. In plant cells, the cell wall keeps this from happening

Water tends to move from hypotonic areas (less concentration) to hypertonic

areas (higher concentration)

Describe how facilitated diffusion and active transport differ from osmosis and diffusion.

Facilitated diffusion and active transport require carrier molecules, osmosis and diffusion do not.

Define tonicity, hypertonic, isotonic, and hypotonic and explain water movement across a plasma membrane in response to tonicity.

Tonicity - a measure of the osmotic pressure of two solutions separated by a semi-permeable membrane

Hypertonic - extracellular fluid has a higher osmolarity (concentration) than the

fluid in the cell. Causing the water to move out to dull the extracellular fluid. The cell will shrivel up as a result and could possibly become destroyed as a result

Isotonic - the concentration of the solute is the same inside and outside of the

cell. There is an even amount of water moving in and out of the cell, so the size remains the same

Hypotonic - the extracellular fluid has a lower osmolarity (concentration) than the cell's cytoplasm. Water will move into the cell. Could get so big it gets destroyed. In plant cells, the cell wall keeps this from happening

Briefly explain endocytosis and exocytosis.

Endocytosis - Endocytosis is a cellular process in which substances are brought into the cell

Exocytosis - Exocytosis is a form of active transport and bulk transport in which a cell transports molecules out of the cell by secreting them through an energy-dependent process

Name the ultimate source of energy for most life on earth and explain the role of photosynthesis in converting this energy into a form that is usable form of life on earth.

The sun is the ultimate source of energy for life on earth.

Photosynthesis is the process of capturing light and converting it. its the only process that can convert light energy to carbohydrates.

ALL living organisms benefit from photosynthesis directly or indirectly

Write the overall equation for photosynthesis and explain the role of each of the reactants (where it comes from and what it is used for) and products (how it is formed and where it goes) in the photosynthetic process.

Carbon dioxide + water + solar energy -> carbohydrate + oxygen

Reactants-

Carbon dioxide - source of carbon atoms for carbohydrates, CO2 comes from atmosphere

Water - splits to release electrons for use in electron transport chanin. hydrogen is also released and used in ATP production

Solar energy - the source of light energy, eventually used to make up high-energy carbohydrates

Products -

Carbohydrate - end product of photosynthesis. can be converted to different forms for storage or into cellulose to make cell walls

Oxygen - biproduct of photosynthesis, water is split

Describe the basic structure of a chloroplast and the function of each of the following: chlorophyll, thylakoid, stroma, and granum.

Chloroplasts are green becuase they REFLECT green light.

Chlorophyll - green pigment found in the thylakoid membrane which absorbs light energy and passes that light energy to electrons

Thylakoid - the membrane system found in chloroplast where the light reactions of photosynthesis take place

Stroma - the fluid space surrounding the thylakoid membrane inside chloroplast, this is where carbon reactions take place

Granum - stack of thylakoid membranes

Describe how the characteristics of light (wavelength and intensity) can influence photosynthesis, including a description of which wavelengths are used by photosynthetic organisms.

Red and blue light wavelengths of light are most effective in photosynthesis because it has the most energy to boot photosynthesis

Describe what happens during the light-dependent reactions, including what goes in and what comes out, and where these reactions take place.

The main goal of these reactions is to take light energy and put it in a usable

form that can be used to help make carbohydrates.

Plants can't store light energy, they can only store carbohydrates.

These reactions take place in the thylakoid membrane

Light energy is captured by chlorophyll (a lipophobic molecule found in the membrane) and is eventually used to convert ADP to ATP and convert NADP+ to NADPH

Inputs - water and light energy, Outputs - ATP and NADPH

Describe the basic structure of a photosystem and explain its function in the light reactions.

A photosystem is a group of proteins that are located in the thylakoid

membranes

The structure channels the captured light energy to make it useful in the photosynthetic process

Photosystems help the chlorophyll funnel the captured light energy to a specific spot in the photosystem called the reaction center.

At the reaction center, the captured light energy is transferred to electrons

The photosystems then guide the movement of the electrons carefully harness the captured energy

The electrons are ultimately transferred to NADP+ to produce NADPH via the

electron transport chain

Explain how an electron transport chain is used in the production of ATP and NADPH in photosynthesis.

the main function of the electron transport chain is to harvest energy from electrons by moving electrons from one membrane bound protein to another.

ATP production - some light energy is captured and used to split water (h2o) and create high energy electrons. When electrons move from photosystem 2 to photosystem 1 those electrons are used to pump H+ (hydrogen ions, protons) from one side of the thylakoid to the other.

The movement coupled with splitting of water creates a concentration gradient of H+ (The concentration gradient represents stored energy) As the H+ moves through the ATP synthase, the energy from the

concentration gradient is captured and used to create ATP from ADP

NADPH production - by the time the electrons get to photosystem I, they are low on energy (the energy in them has been used to move H+ across the thylakoid membrane to create and H+ gradient).

When these electrons pass through the reaction center of Photosystem I, additional light energy is passed onto these electrons. Photosystem I then guide the high-energy electrons to NADPH reductase where they are combined with NADP+ and an H+ to create NADPH. NADPH is a high-energy electron carrier molecule

Describe what happens during the Calvin Cycle, including what goes in, what comes out, and where these reactions take place.

The carbon reactions capture carbon dioxide and use the energy captured during the light reactions to build carbohydrates. This occurs in the Stroma of the chloroplast.

Input- carbon dioxide, ATP, and NADPH from light reactions

Output - Carbohydrate

Explain the role of the Calvin Cycle in producing carbohydrates and describe the three main stages.

CO2 fixation - CO2 collected from the atmosphere is combined with a molecule called RuBP

PGAL synthesis (CO2 reduction) - carbohydrates are made using ATP and high energy electrons form NADPH (the atp and nadph come form light-dependent reactions). Initial compound formed is PGAL. Some PGAL is used to make starch/sugar and some is used for the next stage to regenerate RuBP

Regenerate RuBP - 10/12 molecules from PGAL formed during CO2 reduction are recombined to reform RuBP without it, plants cant capture CO2 for another cycle.

Describe the role of ATP and NADPH in photosynthesis, including where they are produced, where they are used, and what they are used for. Use your understanding of this objective to explain how the light-dependent reactions and Calvin Cycle are coupled.

ATP - used as a direct energy source

NADP - used to deliver high-energy electrons (carries electrons to the system that ultimately makes ATP)

both are produced through light energy reactions

Explain why the uptake of carbon dioxide and the release of oxygen can be used to measure rates of photosynthesis.

The uptake of carbon dioxide can be used because it is a reactant

The disappearance of reactants shows how much is being done

The release of oxygen can be used because it is a product. You can always use the increase and products to see how much has been

completed

Write the overall equation for respiration and explain the role of each of the reactants (where it comes from and what it is used for) and the products (how it is formed and where it goes) in the respiration process.

Carbohydrate + oxygen --> carbon dioxide + water + ATP (cellular energy)

Glucose - whats broken down to make energy, energy is within the covalent bonds

Oxygen - final electron acceptor and is used to make water. at the end of the electron transport chain, you need an electron receptor to bond to the H+ ions

ATP - can be used as direct energy. 2 ATP generated from glycolysis and krebs cycle. 32 ATP generated from oxidation of phosphorylation, 36 total from cellular respiration.

Water (H2O) - gets made when oxygen accepts electrons (paired with hydrogen) at the end of the electron transport chain.

Describe the roll of NAD+, NADH, FAD, and FADH2 in respiration.

NAD+, FAD - electron carriers. carry high energy electrons electron transport chain.

NADH, FADH2 - reduced forms of NAD+ and FAD. cant accept electrons, but they can give them up.

Explain what happens during glycolysis (the first stage of respiration), including the purpose, where glycolysis occurs, what goes in (reactants), what comes out (products), ATP output, and where the products of glycolysis go.

First step in ANAEROBIC cellular respiration. happens in the cytoplasm.

In - glucose, 2ADP, 2NAD+,

Out - 2 pyruvate, 2 ATP, 2 NADH

glucose breaks down into 2 pyruvate

If oxygen is available, pyruvate goes to the next step, if not it can be taken to fermentation. NADH goes to the mitochondria where they help generate ATP via the electron transport chain. the NAD is reused when the next glucose molecule gets broken down.

Explain what happens during Oxidation of Pyruvate, including the purpose, where it occurs, what goes in (reactants), what comes out (products), ATP output, and where the products of oxidation of pyruvate go.

each pyruvate gets broken down to Acetyl-CoA. it initiates aerobic respiration. Happens in the Matrix of Mitochondria. Pyruvate (3-carbon) goes to Acetyl-CoA (2-carbon) releasing a carbon as CO2 into the atmosphere. 2 NADH are generated.

In - 2 pyruvate, 2 NAD+

Out - 2 Acetyl-CoA, 2 NADH

Acetyl-CoA goes to krebs cycle, NADH goes to electron transfer chain

Explain what happens during Krebs Cycle, including the purpose, where it occurs, what goes in (reactants), what comes out (products), ATP output, and where the products of the Krebs cycle go.

Happens in matrix of mitochondria. purpose is to break down all remaining glucose

In - 2 Acetyl-CoA, 2 ADP, 6 NAD+, 2 FAD+

Out - 4 CO2, 2 ATP, 6 NADH, 2 FADH2

CO2 goes out atmosphere, reduced electron carriers (NADH, FADH2) go to electron transfer chain

Explain what happens in Oxidative Phosphorylation (OP), including the purpose, where the OP is located, what goes in (reactants), what comes out (products), ATP output, and where the products of oxidative phosphorylation go.

Electron transport chain harvests energy from electrons, which come from glucose, pyruvate, and acetyl-CoA. Electrons are carried by NADH and FADH2. The electron transfer chain uses these as energy to move H+ ions (higher concentration outside than inside). This gradient is potential energy.

When H+ ions flow back across inner membrane creates enough energy to ADD a phosphate to ADP which makes ATP. 32/36 ATP are made through this.

When the electrons pass through the end of the electron transfer chain, they are transferred to oxygen and make water (H2O)

Describe what happens in each of the following structures: cristae, matrix (inner compartment), and intermembrane space.

Cristae - where the electron transfer chain is found (the folds in the inside of the mitochondria)

Matrix of Mitochondria - where oxidation of pyruvate and the Krebs cycle occur.

Inner membrane - where oxidative phosphorylation occurs

Describe the role of oxygen and water during aerobic cellular respiration

oxygen is a biproduct of photosynthesis, and final electron acceptor.

When oxygen accepts electrons, it also accepts hydrogen ions because electrons cannot be by themselves, forming water.

Name the source of the carbon (C) in the CO2 that is produced during cellular respiration.

CArbon comes from the breakdown of glucose (6-carbon)

glucose (product of photosynthesis) goes in and is a reactant of cellular respiration

Describe the differences between aerobic cellular respiration and fermentation, including the conditions under which each occurs, the number of ATP produced per glucose molecule and what types of organisms use each of these metabolic pathways.

Aerobic cellular respiration is when oxygen IS available after glycolysis; 36 ATP are produced.

Fermentation is when oxygen IS NOT available after glycolysis (this is what leads to things like post-workout fatigue). the purpose is to regenerate NAD+, NOT obtain energy. 2 ATP are produced but they're the ones from glycolysis.

Explain why cells use fermentation (the conversion of pyruvate to ethanol or lactate) to complete the respiratory processes when oxygen is unavailable, even though it (fermentation) does not produce additional ATP.

The function of fermentation is to regenerate NAD+, which takes electrons to the electron transfer chain where most ATP is produced. there are limited NAD+ so without regeneration it would not be able to happen.

fermentation makes lactate (animal/bacteria) and ethanol (fungi)

Identify the final electron acceptor in aerobic cellular respiration and in fermentation and relate this to ATP yield.

Aerobic cellular respiration - Oxygen

Fermentation - pyruvate (gets electron from NADH)

Electrons always come with hydrogen, this is why we get water, ethanol, and lactic acid.

Define the following terms used to describe organisms: obligate aerobic, obligate anaerobic, and facultative

Obligate aerobic - requires molecular oxygen (O2) for metabolic processes; cannot survive without oxygen

Obligate anaerobic - can only survive in the absence of molecular oxygen; oxygen is toxic

Facultative - can survive with or without oxygen. does better with oxygen present but can survive without it (glycolysis)

Describe how varying conditions (temperature, sugar availability, oxygen level) can influence respiration rates in yeast.

Temperature - higher temperature, higher rate

sugar availability - more sugar, higher rate

oxygen level - cant function without oxygen, more oxygen increases rate

Describe the purpose of cellular respiration.

Produces usable energy to carry out metabolic processes, all cells need energy to do their function

breakdown of glucose

Explain the relationship between photosynthesis and respiration.

reactants of one are the products of the other (opposites)

plants use light energy and change it to chemical energy through photosynthesis

other organisms obtain chemical energy and change it to usable forms of energy (ATP) through cellular respiration

Describe the characteristics of bacteria and archaea, the two major groups of prokaryotes.

they have no nuclei or organelles. they have one (1) chromosome so theyre haploid, single cell organisms. they reproduce through binary fission.

bacteria have 3 shapes - Coccus (sphere), bacillus (rod), and spirillum (spiral)

Describe the metabolic diversity of bacteria and archaea, focusing on the metabolic pathway known as chemosynthesis.

Photoautotrophs - uses processes similar to photosynthesis to make carbohydrates from CO2, H2O and solar energy. source of energy is chemical compounds

Chemoautotrophs - uses energy from oxidation of inorganic chemical compounds such as hydrogen sulfide to produce carbohydrates from CO2 and H2O. source of energy is chemical compounds

Heterotrophs - Get energy form breaking down complex organic compounds they take in from the environment

Examine the wide range of habitats where bacteria and archaea can be found.

they can be found in extreme conditions (but not all are) such as the dead sea, hydrothermal vents deep in the ocean, and acidic habitats

Explore the roles of bacteria and archaea in the hydrothermal vent ecosystem and understand the importance of chemosynthesis in this ecosystem.

hydrothermal vent system - hot springs deep inside the ocean where light cannot reach. magma reaches 1000ºC and forms new ocean floor.

bacteria and archea (mostly archea) use energy from the oxidation of H2S (hydrogen sulfide) to turn CO2 into sugars to feed the ecosystem. (clams and tubeworms are primary producers and feed on these archea, and convert CO2 into food.)

Be able to list some of the many important biological and ecological functions performed by bacteria and archaea.

they are decomposers. without decomposers, all the nutrients would be lost because they wouldn't get recycled into the world.

Describe the beneficial and harmful effects of archaea and bacteria on humans.

we depend on some bacteria for nutrients, they also aide in making some foods (bread, beer). they help with the nitrogen levels of soil. On the other hand, they can make us sick if harmful ones invade our bodies.

Understand the current hypothesis for the evolutionary relationship among bacteria, archaea, and eukaryotes.

RNA for archea and bacteria are very different. its believed archea diverged from bacteria in early history because they are only distantly related. Its also appears that archea are more closely related to eukaryotes than bacteria.

Describe the characteristics of fungi and the generalized life cycle of fungi.

most fungi are multicellular and their bodies are made of hyphae (a mass of hyphae are called mycelium). they're heterotrophs. they use multicellular digestion to break down organic food matter, then they absorb smaller molecules by means of their hyphae.

Saprobes are fungi that extract nutrients from dead things. parasitic fungi get nutrients from tissue of their hosts.

fungi spend most of their life as haploids

they can reproduce both sexually and asexually. spores play a role in reproduction no matter how they do reproduce.

Describe how fungi obtain nutrition and the role of fungi in ecosystems.

most are heterotrophs, gaining nutrients form the dead. they play a huge role in nutrient cycling

Describe the beneficial and harmful effects of fungi on humans.

help process foods and make some products (bread, beer), penicillium fungi is the basis of penicillin (an antibiotic)

it can cause diseases (athletes foot) and airborne spores can cause respiratory issues

Describe how proteins and fats are broken down during cellular respiration to release the energy stored in these molecules.

both are sources of energy. they're both polymers that have to be broken down to monomers to be used in cellular respiration. After they're broken down they enter various components of the aerobic respiration pathways

Your body prefers glucose, but can use both proteins and fats also.