Biology 105 HSU Exam 3

How many ATP molecules are produced by the CAC for every glucose molecule metabolized?

2 ATP

what is the overall net ATP production from glycolysis?

2 ATP & 2 NADH

In the Citric Acid Cycle, how many molecules of NADH are produced by pyruvate oxidation for every glucose molecule metabolized?

2 NADH

Describe where pyruvate is oxidized to acetyl-CoA, what molecules are produced and how it links glycolysis to the citric acid cycle

2 NADH, 2 CO2, acetyl CoA. Oxidized upon entering mitochondria matrix. Each of the steps of respiration are very linked together.

What happens in stage 1 of the Calvin Cycle?

6 ATP are used to create ABP + Pi

How many NADH and FADH2 molecules are produced by the CAC for every glucose molecule metabolized?

6 NADH & 2 FADH2

What happens in stage 2 of the Calvin Cycle?

6 NADPH gets reduced to NADP+

Explain how the exergonic oxidation of glucose is coupled to the endergonic synthesis of ATP

Exergonic oxidation releases energy and that energy is released to make ATP.

What are the three stages of the Calvin cycle?

fixation, reduction, regeneration

which molecule is oxidized in the cellular respiration reaction

glucose is oxidized to CO2

feedback inhibition

helps regulate metabolism

allosteric regulation of enzymes

• regulatory molecules bind weakly to an allosteric site (a site other than the active site) activation or inhibition

Where do the light reactions of photosynthesis occur?

Thylakoid ---> thylakoid membrane

Describe the energy profile of a chemical reaction

-Activation Energy (EA): the amount of energy required for the reactants to contort to the transition state (initial investment of NRG for starting reaction) -Free Energy: the portion of a system´s energy that can perform work when temperature and pressure are uniform throughout the system. -Transition State: IN A CHEMICAL RXN: reactants must overcome EA to reach Transition State, ᐃG is positive or negative

noncompetitive inhibitor

A substance that impedes the activity of an enzyme without entering an active site. By binding elsewhere on the enzyme, a noncompetitive inhibitor changes the shape of the enzyme so that the active site no longer functions.

What happens in the stage 3 of the Calvin cycle?

ATP gets turned in ADP

What is the benefit of photosynthesis creating some ATP by oxidative phosphorylation?

ATP=> used to generate carbohydrates

List the wavelengths of light that are most effective for photosynthesis

Absorbs in blue (400-450 nm) and red (650-700 nm) wavelengths. Chlorophyll appears green because it reflects green wavelengths (500 to 600 nm)

what is pyruvate converted into during the CAC and how many carbons does the new molecule have?

Acetyl CoA & 2 molecules

Describe the relationship between an absorption spectrum and a photosynthetic action spectrum

Action Spectrum of Photosynthesis follows Absorption Spectrum of Chlorophyll. The absorption spectrum indicates how much of each wavelength chlorophyll will absorb, whereas the action spectrum can tell us which off those wavelengths are most effective in photosynthesis.

What are the three types of Transport?

Active, Passive, Facilitated

What happens to the electrochemical gradient of protons? Where do the protons want to move?

Bind to the ATP synthase

Describe the summary equation for respiration

C6H12+ 6O2 -> 6CO2 + 6H2O + ATP+Heat

Describe the function of enzymes in biological systems

CATALYSTS lower the activation energy needed→ speed up reactions easier for body to break things down for energy, create things

Explain the role of CO2, NADPH and ATP in the Calvin cycle

CO2 is added to the system and begins the Calvin cycle. It is eventually reduced to sugar through the Calvin cycle. NADPH acts as a reducing agent. ATP acts as a source of chemical energy.

Paracrine

Cells release signals that affect nearby target cells

Autocrine

Cells release signals that affect themselves and nearby target cells

Which pigment is directly involved in the light reactions of photosynthesis?

Chlorophyll

Describe the structure and function of a photosystem

Chlorophyll is the major photosynthetic pigment, sulight, accessory pigments allows photosynthetic cells to absorb a broader range of visible light than would be possible with just chlorophyll alone. Antenna= Absorbed light energy is transferred from one chlorophyll molecule to another. the reaction center is where light energy is converted into electron transport.

Describe the location and structure of the chloroplast

Chloroplasts are found in the cells of plants. Specifically, in leaves, chloroplasts are found in mesophyll cells, which are located on the interior tissue of the leaf. Structure: Chloroplasts have an outer membrane, intermembrane space, and an inner membrane. Inside the chloroplasts there are stacks of thylakoids called granum. Inside the thylakoids there is thylakoid space. Stroma surrounds the granum stacks.

Compare cyclic and noncyclic electron flow and explain the relationship between these components of the light reaction

Cyclic electron flow: only photosystem I, only ATP is produced, oxygen is not involved; noncyclic electron flow, both photosystems I and II, ATP and NADPH are produced, Oxygen is a by-product.

In stage 1 of cellular respiration, where in the cell does reaction 1 occur?

Cytoplasm

Endergonic reactions

Delta G is positive and non-spontaneous, requires energy input, yield product rich in potential energy, decreases amount disorder (entropy decreases stability

Describe what happens during the Calvin cycle

Describe what happens during the Calvin cycle

Explain how active transport differs from diffusion

During active transport the particles (molecules) in solution move in the opposite direction observed with diffusion, moving from low solute concentration to higher solute concentration. To do this active transport requires the use of energy.

Explain how Enzymes lower the energy of activation of reactions

Enzymes lower the activation energy of a reaction by binding one of the reactants, called a substrate, and holding it in a way that lowers the activation energy

Explain what causes diffusion

Extent of the concentration gradient, Mass of the molecules, Temperature, Solvent density, solubility, surface area and thickness of plasma membrane, and distanced traveled

What is the purpose of the Calvin cycle?

G3P -> glucose -> carbohydrates

What molecule is recycled in the Calvin cycle, and what is it recycled into?

G3P recycled into Rubisco bio phosphate

What molecules are produced by the Calvin Cycle

G3P, NADP+, ADP, Pi

What is the purpose of the proton gradient that is created by chemiosmosis? In what other metabolic pathway does similar chemiosmosis occur?

Generate the protein motive force used for ATP synthesis . Similar process: Respiration

What are the molecules in the plasma membrane?

Glycolipid, peripheral protein, transmembrane protein phospholipid, cholesterol

Write a summary equation for glycolysis and describe where it occurs in the cell

Glycolysis occurs in the cytosol. 2 ATP are netted. Equation = Glucose -> 2 pyruvate + 2 ATP

What happens to the protons (H+) around the electron transport chain? Where do they go? How do they get there?

H+ gets pumped into the inter membrane space by the proteins in the electron transport chain

What is the function of photosystem 1?

Harvesting light energy and excites electrons and eventually NADP+ to NADPH Rxn center=P700

In cellular respiration, where in the mitochondrion does reaction 4 occur?

I.M.M

At the end of the Citric Acid Cycle, NADH and FADH2 are charged with electrons. Where do they take those electrons?

I.M.M and the Electron Transport Chain (ETC)

Explain how fermentation differs from aerobic respiration

In fermentation, ATP is only made by substrate-level phosphorylation during glycolysis. In aerobic respiration, much more ATP is made per each glucose molecule that is oxidized, because aerobic respiration uses oxidative phosphorylation as well as substrate-level phosphorylation. Fermentation occurs in facultative anaerobes when oxygen is limited or absent. In aerobic respiration, the oxidation of NADH made during glycolysis and the citric acid cycle is used to create the proton gradient that drives oxidative phosphorylation. High energy electrons derived from glucose are passed through an electron transport system to oxygen, forming water. In fermentation, because no external e- acceptor is available, NADH is oxidized to NAD+ by removing the high energy electrons and adding them to pyruvate, forming lactate or ethanol

Define diffusion

Is a passive process of transport. A single substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across a space.

Explain the role of NAD+ in respiration

It is a coenzyme and an electron carrier. NAD+ is a good electron carrier bc it can cycle easily between oxidized (NAD) and reduced (NADH) states. As an electron acceptor, NAD+ functions as an oxidizing agent during respiration

Explain the relationship between free energy and a spontaneous reaction

It is a exergonic reaction and delta G is less than zero, so the reaction is spontaneous

What is the function of the plasma membrane?

It separates the contents of the cell from its outside environment and it regulates what enters and exits the cell. Plasma membrane plays a vital role in protecting the integrity of the interior of the cell by allowing only selected substances into the cell and keeping other substances out. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane supports the cell and helps in maintaining the shape of the cell. The cell membrane is primarily composed of proteins and lipids. While lipids help to give membranes their flexibility and proteins monitor and maintain the cell's chemical climate and assist in the transfer of molecules across the membrane. The lipid bilayer is semi-permeable, which allows only selected molecules to diffuse across the membrane.

What role does the pigment play in the light reactions

Light harvesting molecules, excites e-, passed to primary e- acceptor

What happens to the G3P molecules produced by the Calvin Cycle?

Most get recycled, 1 G3P is used to synthesize glucose

What happens to the electrons that are lost from pyruvate when it is oxidized?

NAD+ gets reduced to NADH

What are the final electron acceptors in the light reactions, and where are the electrons utilized

NADP+ accepts e-'s=> NADPH

Reduction

Occurs when an atom gains electrons.

Oxidation

Occurs when an atom loses electrons

Why is diffusion a spontaneous process?

One solute is independent of the concentration gradients of other solutes and because it involves a passive transport process, which implies that energy is not expended when substances diffuse down their concentration gradient

The active site can lower an EA barrier by

Orienting substrates correctly Straining substrate bonds Providing a favorable microenvironment Covalently bonding to the substrate

Distinguish between substrate-level and oxidative phosphorylation

Oxidative phosphorylation involves electron transport and chemiosmosis. Substrate level phosphorylation in which a phosphate group is transferred from an organic molecule to ADP

Which molecules "catches" the "spent" electrons? Why is this particular molecule best for the job?

Oxygen because it is electronegative

Describe the structure of a phospholipid.

Phospholipids are amphipathic meaning they have elements that are both hydrophobic and hydrophilic. The hydrophobic part of the molecule consists of two fatty acid chains attached to a molecule of glycerol. Also connected to the glycerol is the hydrophilic head group which consists of a phosphate group and a hydrophilic side chain which varies in different phospholipids.

Describe factors that affect selective permeability of cell membranes

Plasma membranes are asymmetric: the interior of the membrane is not identical to the exterior of the membrane. In fact, there is a considerable difference between the array of phospholipids and proteins between the two leaflets that form a membrane.

Explain how saturated and unsaturated fatty acids can alter membrane fluidity.

Saturated fats are linear and can pack together tightly making a membrane more fluid while unsaturated fats have a cis double bond. This bond will cause bends or kinks in the molecule, therefore preventing the fatty acids from packing together tightly and resulting in a more fluid member.

Explain what an electrochemical gradient is and why it has potential energy

The combined gradient of concentration and electrical charge that affects an ion, It has potential energy because of the difference of charge

Explain why a concentration gradient across a membrane has potential energy

The concentration gradient of a substance across a membrane represents potential energy because it drives diffusion.

Describe the fluidity of the cell membrane?

The molecule represented by e is Cholesterol. Unsaturated fatty acids which have one or more cis-double bonds are usually kinked and will make a membrane more fluid as they do not pack as tightly as saturated fatty acids. Saturated fatty acids have no double bonds and are, therefore, more linear, will make the membrane less fluid. Cholesterol will act as a fluidity "buffer" by packing between fatty acid molecules. Making a membrane with a high content of unsaturated fatty acids more solid and a membrane with a high content of saturated fatty acids more fluid

Describe the process of chemiosmosis and how membrane structure is related to function in the process of chemiosmosis

The movement of hydrogen/protons through the concentration gradient. It is an acidic gradient as well. The protons are released on one side of the membrane. They come back through ATP synthase and make ATP.

Explain how the potential energy of a transmembrane solute gradient can be harvested by a cell and used to transport substances across the membrane

This is the electrochemical gradient, which is a variation of both electrical potential and chemical concentration across a membrane. And the result can be a type of potential energy available for work in a cell

What occurs in the "energy investment" phase or glycolysis?

Use ATP to produce G3P

Trace electron flow from water through photosystems 1 and 2

Water is split to reduce the oxidized P680 reaction center chlorophyll in photosystem II. The electrons are passed from P680 to a primary electron acceptor, and from that primary electron acceptor to an electron transport chain embedded in the thylakoid membrane. The electrons are passed from one member of the electron transport chain to the next, and some of the released energy is used to create a proton gradient that will be used to make ATP via ATP synthase. The electrons end up on a P700 reaction center chlorophyll. The electrons are passed from P700 to a primary electron acceptor, and from that primary electron acceptor to NADP+ reductase, where they are used to reduce NADP+ to NADPH.

competitive inbitibors

bind to the active site; prevents substrate from binding

Write a summary equation for photosynthesis

carbon dioxide + water + light energy ---------> glucose + oxygen + water

What are the inputs of the Calvin Cycle? Where do they come from?

carbon dioxide(Atmosphere) , ATP, NADPH(Both light rxns)

where in the cell is pyruvate oxidized?

matrix

Explain the role of hydrophobic interactions in membrane structure / function

membrane surfaces that face the interior and exterior of the cell are hydrophilic. In contrast, the interior of the cell membrane is hydrophobic and will not interact with water. and create a two-layer cell membrane that separates fluid

In cellular respiration, where in the mitochondrion does reaction 3 occur?

mitochondria matrix

Describe the different ways that proteins are oriented in the cell membrane

orient the protein alongside the phospholipids, with the hydrophobic region of the protein adjacent to the tails of the phospholipids and the hydrophilic region or regions of the protein protruding from the membrane and in contact with the cytosol or extracellular fluid.

Which molecule is reduced in the cellular respiration reaction?

oxygen is reduced to water

What are the components of the Plasma Membrane?

phospholipid, cholesterol, Peripheral proteins, carbohydrates(components of glycoproteins and glycolipids, Integral proteins

Exergonic reactions

release energy, delta G is negative, -increases amount of disorder (entropy) -begins as unstable --> spontaneous increases stability

explain the relationship between enzyme structure and enzyme specificity

specificity of enzyme results from its shape, a result of amino acid sequence, it can recognize the substrate. key and lock model -the substrate will only stay in the active site if the bonds work

Where do Calvin cycle reactions occur?

stroma of chloroplasts

What is the function of photosystem 2?

to oxidize (breakup) water and transport its electrons to photosystem 1 (P680)