Bio Test #2

*6.3* In eukaryotic cells, _____ produce most _____.

In eukaryotic cells, mitochondria produce most ATP.

The nucleus, ER, and Golgi interact to ____ ____, such as milk proteins.

The nucleus, ER, and Golgi interact to secrete substances, such as milk proteins.

Turgor pressure

Turgor pressure is the resulting force of water against the cell wall.

Cilia

Two types (motile and non-motile) They are short and numerous, like a fringe.

The chemical reaction that generates ATP is straightforward: ...

an enzyme tacks a phosphate group onto ADP, yielding ATP.

*3.5* The ____ supports eukaryotic cells.

cytoskeleton

*3.4* Eukaryotic organelles divide ____.

labor

Nuclear pores and Nuclear envelope

mRNA molecules exit the nucleus through nuclear pores, which are holes in the double-membrane nuclear envelope that separates the nucleus from the cytoplasm.

*3.3* A _____ surrounds each cell and separates its from its surroundings.

membrane

Cells use the _____ in food to generate ATP.

potential energy

Flagella

(whip-like) for motility Unlike cilia, flagella occur singly or in pairs, and a flagellum is much larger than a cilium. Flagella are more like tails and their whiplike movement propels cells. Sperm cells in many species, including humans, have prominent flagella.

Electron transport chains and ATP synthase also occur in the...., which...

***Chapter 5 info** Electron transport chains and ATP synthase also occur in the thylakoid membranes of the chloroplasts, which generate ATP in the light reactions of photosynthesis.

*My own section* Explaining the aerobic respiration process.

***Split up in the flashcards below for ease.

Isotonic

.The cell's interior is normally isotonic to the surrounding blood plasma, which means that the solute concentration inside the cell is the same as that of the plasma.

What are the 2 types of fermentation

1. Alcoholic fermentation 2. Lactic acid fermentation

In tissues, the plasma membranes of adjacent cells directly connect with one another via several types of junctions. What are the 3 main types of juctions?

1. Gap junction 2. Tight junction 3. Anchoring (or adhering) junction.

How do cells transport substances across their membranes?

1. Passive Transport a. simple diffusion b. facilitated diffusion c. osmosis 2. Active Transport (requires energy, which comes from protein "pumps" which consume ATP in order to move a solute against its concentration gradient) 3. Endocytosis/exocytosis

The two physical laws that are especially relevant to the study of biology

1. The law of energy conservation. -This law states that energy cannot be created or destroyed, although energy can be converted to other forms. In fact, every aspect of life centers on converting energy from one form to another. The most important energy transformations in life are photosynthesis and cellular respiration. 2. 2nd law states that all energy transformations are inefficient because every reaction loses some energy to the surroundings as heat

The electron transport chain produces ___ ATP

34

Cellular respiration of 1 glucose yields ___ ATP. Explain.

36 Glycolysis and Krebs cycle each produce 2 ATP, and the electron transport chain produces 34 ATP. Transporting NADH into the mitochondrion requires 2 ATP, making the total production of ATP equal to 36.

Selectively permeable

A cell's interior is chemically different from its exterior. It maintains this difference by regulating transport of dissolved substances (solutes) across its membrane. Regulating which substances can pass through a membrane is known as being "selectively permeable" A biological membrane is a phospholipid bilayer studded with proteins. This structure means that a membrane is "choosy", or selectively permeable.

Ribosomes

A messenger molecule carries the protein "recipe" to a ribosome, where a protein is assembled. The ribsomal subunits leave the nucleus through the nuclear pores, and they come together in the cytoplasm to form complete ribosomes. Some ribosomes are on the surface of the rough ER.

Endoplasmic reticulum (ER) Rough & Smooth

A network of sacs and tubules composed of membranes. Located in the cytoplasm. It is like a network. Rough ER: Some ribosomes are on the surface of the rough ER. Close to the nucleus, the membrane surface is studded with ribosomes making proteins that enter the inner compartment of the ER; these proteins are designed to be secreted from the cell. Proteins synthesized at the rough ER will be secreted from the cell. The proteins exit the organelle in bubbles of membrane called vesicles. Smooth ER: Adjacent to the rough ER, a section of the network called smooth ER synthesizes lipids and other membrane components. The smooth ER also houses enzymes that detoxify drugs and poisons.

Pyruvate

A type of molecule. During glycolysis, a glucose molecule is split into two three-carbon pyruvate molecules.

No cell can survive without _____.

ATP (adenosine triphosphate)

ATP Formation and ATP Breakdown

ATP formation is coupled with energy-releasing reactions ATP breakdown is coupled with energy-requiring reactions

Why is ATP essential? Give some examples of things that need ATP.

ATP is essential because it powers nearly every activity that requires energy INPUT in the cell. Examples: Synthesis of DNA, RNA, proteins, carbohydrates, and lipids; active transport across the membranes surrounding cells and organelles; separation of duplicated chromosomes during cell division; movement of the cilia and flagella; muscle contraction; and many others.

ATP synthesis requires...

ATP synthesis requires energy input. Cellular respiration releases energy from glucose in several steps: 1. Glycolysis 2. Krebs Cycle 3. Electron Transport

Biologists organize the intricate biochemical pathways of respiration into three main groups. Cellular respiration occurs in what three stages?

ATP synthesis requires energy input. Cellular respiration releases energy from glucose in three steps. Step 1: Glycolysis Step 2: Krebs Cycle Step 3: Electron Transport Chain

Aerobic respiration yields much more ____ than ____ alone.

Aerobic respiration yields much more ATP than Glycolysis alone. The reactions of Krebs cycle and the electron transport chain ***add info from slide*** The two pyruvate molecules produced in glycolysis undergo an oxidation reaction as they enter the mitochondrion. ***add info from slide***

After the Krebs cycle, so far, aerobic respiration of one glucose molecule has yielded ___ ATP. But ____ ____ molecules have been produced, as well as ___ ____.

After the Krebs cycle, so far, aerobic respiration of one glucose molecule has yielded 4 ATP. But 10 NADH molecules have been produced, as well as 2 FADH2.

ADP

All cells depend on the potential energy in ATP to power their activities. When cells require energy for a chemical reaction, it "spends" ATP by removing the endmost phosphate group. The products of this hydrolysis reaction are adenosine diphosphate (called ADP since only two phosphate groups remain attached to ribose), the liberated phosphate group, and a burst of energy. (ATP + H2O --> ADP + [P] + energy) In a reverse situation, energy can be temporarily stored by adding a phosphate to ADP, forming ATP and water. (ADP + [P] + energy --> ATP + H2O). The energy from this reaction comes from molecules broken down in other reactions, such as those in ceullar respiration.

Diffusion

All forms of passive transport involve diffusion, which is the spontaneous movement of a substance from a region where it is more concentrated. Because diffusion represents the dissipation of a chemical gradient - and the loss of potential energy - it does not require energy input.

Nucleolus

Also inside the nucleus is the nucleolus, a dense spot that assembles the components of ribosomes.

Electron Transport Chain

An electron transport chain is a series of membrane proteins participating in sequential oxidation-reduction reactions. Both rxn's occur simultaneously. Enery is released at each step. Some proteins are electron-shuttling "specialists". Groups of these electron carriers often align in membranes. In an electron transport chain, each protein accepts an electron from the molecule before it and donates the electron to the next in line. As a result, each protein in the chain is first reduced and then oxidized. Small amounts of energy are released at each step. Photosynthesis and cellular respiration both use electron transport chains.

Activation energy

An enzyme speeds up a chemical reaction by lowering the activation energy, which is the amount of energy required to start a reaction. The enzyme brings reactants (also called substrates) into contact with one another, so that less energy is required for the reaction to start. The lower the activation energy, the faster the reaction can proceed.

Anchoring junction

Anchoring junctions use intermediate filaments to hold cells together.

Entropy

Because heat is disorder and all energy eventually becomes heat, it follows that all energy transformations must head toward increasing disorder. Entropy is a measure of this randomness. Entropy is a measure of the randomness, or disorder, of the universe So, the more disordered a system is, the higher its entropy. Since heat energy is constantly being lost to the universe, and heat energy is disordered, the entropy of the universe is increasing. The universe is moving towards a state of entropy

Because of their chemical structure, phospholipids spontaneously form ____ in ____.

Because of their chemical structure, phospholipids spontaneously form bilayers in water.

Besides phospholipids, cell membranes also contain ____. Give some examples.

Besides phospholipids, cell membranes also contain proteins. Examples: Transport proteins Enzymes Recognition proteins Adhesion proteins Receptor proteins

Intermembrane compartment

Between the mitochondrial membranes is an intermembrane compartment.

Calorie

Both forms of energy (kinetic/potential) are measured in units called calories (cal). 1 calorie is the amount of energy required to raise the temperature of 1 gram of water from 14.5 degrees Celsius to 15.5 degrees Celsius

What is the chemical symbol for glucose?

C6,H12,O6

What is the formula for aerobic respiration? (using symbols with the amount first, and then names)

C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36ATP (Glucose) + (Oxygen) ---> (Carbon Dioxide) + (Water) + (ATP)

What does the symbol CO2 represent?

Carbon Dioxide

Main energy required reaction

Carbon Dioxide + Water --> Glucose + Oxygen (Photosynthesis) Energy required reactions are usually reactants that build complex molecules from simpler components. The products contain more energy than the reactants.

Cell membranes are composed of molecules called _____.

Cell membranes are composed of molecules called phospholipids.

*3.6* ____ stick together and communicate with one another.

Cells Just as organelles in a cell work together, the cells that make up multicellular organisms also divide labor, which requires communication among neighboring cells.

Chapter 3

Cells (picking up where we left off from Test #1)

*6.1* Cells use energy in ____ to make ____.

Cells use energy in food to make ATP.

Chemical reactions

Chemical reactions may require energy to be gained and others may require energy to be released. Energy requiring reaction: Photosynthesis Energy releasing reaction: Cellular respiration

Cristae

Cristae are folds that greatly increase the surface area of the inner membrane. The inner membrane's cristae provides tremendous surface area on which the reactions of the electron transport chain occur.

Cellular respiration

During cellular respiration, the energy rich glucose molecules change back to carbon dioxide and water, liberating the energy necessary to power life. Cells translate the potential energy in glucose into the kinetic energy of molecular motion and use that burst of kinetic energy to do work.

During fermentation, oxidation of a ____ molecule yields only ___ ATP.

During fermentation, oxidation of a glucose molecule yields only 2 ATP.

What is a basic overview of what happens in glycolysis?

During glycolysis, a glucose molecule is split into two three-carbon pyruvate molecules. The enzymes of glycolysis extract some of the potential energy stored in glucose. The process yields two ATP molecules and two electron-carrying NADH molecules.

Group/Stage 1: Glycolysis

During glycolysis, glucose is split into two three-carbon molecules of pyruvate. This process harvests energy in two forms. First, some of the electrons from glucose are transferred to an electron carrier molecule called NADH. Second, glycolysis generates two molecules of ATP. Glycolysis occurs outside of the mitochondrion, in the cytoplasm. Glycolysis splits gluscose These reactions do NOT REQUIRE OXYGEN ***Know the outputs and inputs of glycolysis in each steps are***

During the Krebs cycle, the two acetyl CoA molecules are ____, yielding...

During the Krebs cycle, the two acetyl CoA molecules are oxidized, yielding 4 CO2, 2 ATP, 6 NADH, and 2 FADH2.

Oxidation-Reduction Reactions

Electrons can carry energy. Most energy transformations in organisms occur in oxidation-reduction ("redox") reactions, which transfer energized electrons from one molecule to another.

Endocytosis

Endocytosis allows a cell to engulf fluids and large molecules and bring them into the cell. Large substance entering a cell.

Energy

Energy is the ability to do work, that is, to move matter.

Enzyme

Enzymes are the most important of all biological molecules. An enzyme is a protein that speeds up a chemical reaction without being consumed. Most enzymes are proteins, although some are made of RNA. Substrate molecules bind to the enzyme's active site, where the chemical reaction occurs. Once the chemical reaction occurs, product molecules are released. The enzyme retains its original form. Note that not all enzymes break a single substrate into two products. Other enzymes combine two sub...***finish sentence with info from slide***

Eukaryotic cells contain ____ with specialized functions.

Eukaryotic cells contain organelles with specialized functions.

Exocytosis

Exocytosis uses vesicles to transport substances out of cells. Large substance leaving a cell.

Facilitated diffusion

Facilitated diffusion is a form of passive transport in which a membrane protein assists the movement of a polar solute along its concentration gradient. A not large substance that is moving down its concentration gradient and is polar.

Fermentation generates ____ only in ____.

Fermentation Generates ATP Only in Glycolysis

What are the steps of the Krebs cycle?

First (step 1): Acetyl CoA combines with a 4-carbon molecule, yielding citrate (6-carbon molecule) Then (step 2-6): Citrate is then rearranged and oxidized, yielding 3 NADH, 1 FADH2, and 1 ATP per turn. Ending: The original four-carbon molecule is re-created, and the cycle starts anew.

Gap junction

Gap junctions connecting animal cells are analogous to plasmodesmata. A protein channel links the cytoplasm of neighboring cells.

What does the symbol C6,H12,O6 represent?

Glucose

Glycolysis always occurs in the _____, but the location of the other two pathways depend on the ____ ____. Explain.

Glycolysis always occurs in the cytoplasm, but the location of the other two pathways depend on the cell type. In bacteria and archaea, the enzymes of the Krebs cycle are in the cytoplasm, and electron transport proteins are embedded in the cell membrane. The eukaryotic cells of protists, plants, fungi, and animals, however, contain organelles called mitochondria that house the other reactions of cellular respiration (Kerbs cycle and electron transport)

Group/Stage 3: Electron Transport Chain

Glycolysis and the Krebs cycle transfer some of the potential energy in glucose to ATP. Meanwhile, electrons are transferred to NADH and FADH2. NADH and FADH2 unload electrons at the electron transport chain, where the potential energy in the electrons is used to produce more ATP. The electron transport chain transfers high-energy electrons from NADH and FADH2 through a series of membrane proteins. As electrons pass from carrier to carrier in the electron transport chain, the energy is used to create a gradient of hydrogen ions. The mitochondrion uses the potential energy stored in this proton gradient to generate ATP. An enzyme called ATP synthase forms a channel in the membrane, releasing the protons and using their energy to ass phosphate to ADP. As described later, the same enzyme (ADP) generate ATP in the light reactions of photosynthesis. In the meantime, the "spent" electrons are transferred to oxygen (O2), generating water as a waste product.

Glycolysis overview

Glycolysis is a more-or-less universal metabolic pathway that splits glucose into 2 three-carbonpyruvate molecules. The name of the pathway reflects its function: "glyco" means sugar, and "-lysis" means to break.

Where does glycolysis occur?

Glycolysis occurs outside of the mitochondrion, in the cytoplasm.

Glycolysis requires an input of ___ ATP to _____ _____.

Glycolysis requires an input of two ATP to "activate" glucose.

What is the yield of glycolysis?

Glycolysis yields two ATP molecules, two electron-carrying NADH molecules, and two pyruvates.

Microtubules

Hollow cylinders about 23 nm in diameter that consist of tubulin subunits. They are involved in maintaining cell structure, and make up the internal structure of cilia and flagella The cell can shorten or lengthen microtubules by adding or taking away tubulin molecules. Lots of functions: -Pull a cell's duplicated chromosomes apart during cell division -Form a "track" for organelles and proteins to move rapidly Microtubules form the internal framework of cilia and flagella. Though a cytoskeleton does not support prokaryotic cells, research suggests that they do have cytoskeleton precursor molecules that help maintain the shape of prokaryotic cells.

Chapter 6

How cells release energy

Referring to the mitochondria, in a eukaryotic cell, the...?

In a eukaryotic cell, the two pyruvate molecules produced in glycolysis cross both of the mitochondiral membranes and move into the matrix. Here, enzymes cleave (split a molecule by breaking a particular chemical bond) pyruvate and carry out the Krebs cycle. Then, FADH2 and NADH from glycolysis and the Krebs cycle move to the inner mitochondrial membrane, which is studded with electron transport proteins and ATP synthase. The inner membrane's cristae provide tremendous surface area on which the reactions of the electron transport chain occur.

Active transport

In active transport, the cell uses energy and a transport protein to move a substance against its concentration gradient. For example, the sodium-potassium pump uses ATP to transportNa+ and K+ across the membrane. A not large substance that is not moving down its concentration gradient.

Alcoholic fermentation

In alcoholic fermentation, NADH reduces the 2 pyruvate to 2 ethanol (2-carbon) and also creates 2 carbon dioxide (CO2) molecules . NAD+ is re-created from the electron-carrying NADH. Input: -2 pyruvate -2 electron-carrying NADH Output: -2 ethanol -2 carbon dioxide (CO2) -2 NAD+

Competitive inhibition

In competitive inhibition, the reaction product binds the the enzyme's active site, preventing it from binding substrate. It is "competitive" because the product competes with the substrate to occupy the active site.

Fermentation

In fermentation, electrons from NADH are used to reduce pyruvate. Glycolysis would still yield the same output, but the 2 NADH molecules does not donate its electrons to an electron transport chain, nor is the pyruvate further oxidized in the Krebs cycle. Instead, when the electrons from NADH are "dumped" onto pyruvate, the product is an organic molecule such as an alcohol or an acid that the cell discards as waste.

Lactic acid fermentation

In lactic acid fermentation, NADH reduces the 2 pyruvate to 2 lactic acid (3-carbon) (does NOT produce CO2 like alcoholic fermentation). NAD+ is re-created from the electron-carrying NADH. Input: -2 pyruvate -2 electron-carrying NADH Output: -2 lactic acid -2 NAD+

Inhibitor

In many cases, the inhibitor is the product of the reaction that the enzyme catalyzes.

Noncompetitive inhibition

In noncompetitive inhibition, a product molecule binds to the enzyme at a location other than the active site. This action alters the enzyme's shape so that it can no longer bind the substrate.

Phagocytosis

In phagocytosis, the cell captures and engulfs large particles, such as debris or even another cell.

Photosynthesis

In photosynthesis, plants and some microbes use carbon dioxide, water, and the kinetic energy in the sunlight to assemble glucose molecules. These carbohydrates contain contain potential energy in their chemical bonds.

Phospholipid bilayers

In water, phospholipid molecules spontaneously arrange themselves into a phospholipid bilayer. The outside of the bilayer is the hydrophilic heads, and the inside is the hydrophobic tails.

Explain how cellular respiration is related to breathing.

Inhaled oxygen is consumed in cellular respiration. Carbon dioxide, produced as a byproduct, is then exhaled. ...extended... The cell uses the ATP formed during cellular respiration to do work, such as muscle contraction.

What are the inputs and outputs of the Krebs cycle?

Inputs: -2 Acetyl CoA molecules (2-carbon) -2 ADP + 2 phosphate groups -6 NAD+ -2 FAD Outputs: -4 carbon dioxide (CO2) molecules -2 ATP -6 electron-carrying NADH molecules -2 electron-carrying FADH2 molecules

What are the inputs and outputs of this process in between glycolysis and the Krebs cycle?

Inputs: -2 3-carbon pyruvate molecules -2 NAD+ Outputs: -2 Acetyl CoA molecules (2-carbon) -2 carbon dioxide (CO2) molecules -2 electron-carrying NADH molecules

Keep in mind that ____ ____ ____ molecules are produced from each ____.

Keep in mind that 2 acetyl CoA molecules are produced from each glucose.

Kinetic energy

Kinetic energy is energy being used to do work; any moving object possesses kinetic energy. A bicyclist cruising down a hill demonstrates kinetic energy. Light and sound are other types of kinetic energy. Inside a cell, each molecule has kinetic energy.

Does passive transport require energy?

No

Lysosomes

Lysosomes are organelles containing enzymes that dismantle and recycle food particles, captured bacteria, worn-out organelles, and debris. They are named this because they "lyse", or cut apart, their substrates. The rough ER manufactures the enzymes that end up in the lysosomes. Most plant cells lack lysosomes. Originate in the Golgi apparatus.

____, ____, and ____ are cellular digestion centers.

Lysosomes, Vacuoles, and Peroxisomes

Endomembrane system

Many of these internal membranes form a coordinated endomembrane system, which consists of the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and cell membrane.

Hypotonic

Means that there is a higher solute concentration inside the cell.

Hypertonic

Means that there is a lower solute concentration inside the cell.

Membrane transport may _____ or ____ energy

Membrane transport may release or cost energy.

Mitochondria

Mitochondria are organelles that use a process called cellular respiration to extract this needed energy from food. Most eukaryotic cells have mitochondria, which extract energy from food. The food travels from the chloroplast to the mitochondria, which extract the energy used for cellular processes.

What does Mitochondrial DNA do?

Mitochondrial DNA encodes ATP synthase and most of the proteins of the electron transport chain.

Vacuoles

Most plant cells lack lysosomes. Cellular digestion occurs in large central vacuoles, which also help regulate the size and water balance of plant cells. An organelle that serves a similar function to lysosomes. The large central vacuole contains a watery solution of enzymes that degrade and recycle molecules and organelles. Most of the growth of a plant cell comes from the increase in volume of its vacuole (up to 90% of the cells volume can be occupied by the vacuole).

How do NADH and FADH2 power ATP formation?

NADH and FADH2 donate their electrons to the electron transport chain, where energy from the electrons is used to produce many ATP.

What happens with all those electron-carrying molecules?

NADH and FADH2 donate their electrons to the electron transport chain, where energy from the electrons is used to produce many ATP.

The glycolysis reactions of glucose activation and energy extraction do NOT require ____. Glycolysis can therefor occur in ______ conditions.

Note that these reactions do not require oxygen. Glycolysis can therefore occur in anaerobic conditions.

Sodium-potassium pump

One active transport membrane in the of most animal cells is a protein called the sodium-potassium pump, which uses ATP as an energy source to expel three Na+ for every two K+ it admits.

Negative feedback

One way to regulate a metabolic pathway is by negative feedback (or feedback inhibition), in which the product of a reaction inhibits the enzyme that controls its formation. Negative feedback works in 2 general ways to prevent too much of the reaction product from accumulating: 1. Noncompetitive inhibition 2. Competitive inhibition

Mitochondria

Organelles called mitochondria house the Krebs cycle and electron transport reactions of cellular respiration for EUKARYOTIC cells. Many of the reactions of cellular respiration occur in mitochondria. Mitochondria have two phospholipid bilayers: an outer membrane and a highly folded inner membrane. Many enzymes span the inner membrane, catalyzing the reactions of the electron transport chain. Cristae are folds that greatly increase the surface area of the inner membrane. Between the mitochondrial membranes is an intermembrane compartment. The space within the inner membrane is the mitochondrial matrix, which houses the reactions of the Krebs cycle. In eukaryotic cells, mitochondria produce most ATP. The mitochondria uses the potential energy stored in this proton gradient to generate ATP. The mitochondria contains both DNA and ribosomes. Mitochondrial DNA encodes ATP synthase and most of the proteins of the electron transport chain.

Phospholipids

Organic molecules that resemble triglycerides. In a phospholipid, glycerol bonds to only two fatty acidsl the third carbon binds to a phosphate group attached to additioanl atoms. They have hydrophilic heads and hydrophobic tails.

Organisms can increase in complexity as long as...?

Organisms can increase in complexity as long as something else decreases in complexity by a great amount.

*6.8* Organisms produce ___ in the absence of ____, as well. Glycolysis produces ____ and does not require ____. However, glycolysis does require ____, which is re-created in the electron transport chain of cells undergoing respiration.

Organisms produce ATP in the absence of oxygen, as well. Glycolysis produces ATP and does not require oxygen. However, glycolysis does require NAD+, which is re-created in the electron transport chain of cells undergoing respiration.

Osmosis

Osmosis, the diffusion of water down its concentration gradient, is also a type of passive transport. Osmosis is the simple diffusion if water across a selectively permeable membrane.

*6.7* Other ____ molecules enter the energy-____ pathways.

Other food molecules enter the energy-extracting pathways.

Oxidations and Reductions

Oxidations and reductions occur simultaneously because electrons removed from one molecule during oxidation join another molecules and reduce it. That is, if one molecule is reduced (gains electrons), then another must be oxidized (loses electrons).

Oxidized and Reduced

Oxidized = Loss of electron Reduced = Gain of electron

What does the symbol O2 represent?

Oxygen

Main energy released reaction

Oxygen + Glucose --> Carbon Dioxide + Water (Cellular respiration) Energy releasing reactions usually break large, complex molecules into smaller, simpler components. The products contain less energy than the reactants.

ATP synthase

Part of the electron transport chain. An enzyme called ATP synthase forms a channel in the membrane, releasing the protons and using their potential energy to add phosphate to ADP. As described later, the same enzyme (ADP) generate ATP in the light reactions of photosynthesis. In the meantime, the "spent" electrons are transferred to O2, generating water as a waste product.

Peroxisomes

Peroxisomes also aid in digestion. They originate at the ER and contain several types of enzymes that break down toxic substances. All eukaryotic cells contain peroxisomes. Resemble lysosomes but peroxisomes originate in the ER, not the Golgi apparatus, and contain different enzymes.

Plasmodesmata

Plant cells communicate through plasmodesmata, channels that connect adjacent cells. Nutrients and biochemicals travel through these channels to adjacent cells. They are essentially "tunnels" in the cell wall, through which the cytoplasm of one plant cell can interact with that of another. `

All cells need ATP, but they don't all produce it in the same way. Explain and give examples.

Plants, animals, and many microbes, especially those in oxygen (O2) rich environments, use food (such as glucose) and oxygen gas to produce ATP through, aerobic respiration. Aerobic respiration is when a cell uses oxygen gas (O2) and glucose to generate ATP. Other pathways, including fermentation, generate ATP from glucose without using oxygen (O2).

Potential energy

Potential energy is stored energy available to do work. A bicyclist at the top of a hill illustrates potential energy. Likewise, unburned gasoline, or an energy bar you would grab for breakfast, contains potential energy stored in the chemical bonds of its molecules.

____ and ____ are also used as energy sources for the cell. These molecules enter the energy-extracting pathways and produce ____.

Proteins and fats are also used as energy sources for the cell. These molecules enter the energy-extracting pathways and produce ATP.

Hydrogen ion

Recall from chapter 2 that a hydrogen ion is simply a hydrogen atom stripped of its electron, leaving just a proton.

Reduction

Reduction means a gain of electrons (plus any energy contained in the electrons) by an atom or molecule . Reduction reactions therefore require a net input of energy.

Simple diffusion

Simple diffusion is a form of passive transport in which a substance moves down its concentration gradient without the aid of a transport protein. Substances may enter or leave cells by simple diffusion only if they can pass freely through the membrane. Lipids and small, nonpolar molecules such as oxygen (O2) and carbon dioxide (CO2), for example, diffuse easily accross the hydrophobic portion of a biological membrane. A not large substance that is moving down its concentration gradient and is nonpolar.

What is the glucose activation process of glycolysis? After the glucose activation process, what is the energy extraction reactions process of glycolysis?

Start: There is a 6-carbon glucose molecule. 1. A phosphate is transferred from ATP to the glucose molecule and is put on one of the ends. 2. A 2nd phosphate is transferred from ATP to the glucose molecule and it put on the other end. (Phosphate is now on each end of the 6-carbon glucose molecule). 3. The 6-carbon glucose molecule splits into two 3-carbon molecules. (the two high energy phosphate groups redistribute energy in the molecule and cause it to split in half). There is now 1 phosphate on each of the two 3-carbon molecules. ***End glucose activation; Begin energy extraction*** 4. First, each 3-carbon molecule is oxidized, producing two NADH molecules. (the two NADH molecules come from "NAD+", which i think it just the symbol for an oxidized NADH molecule). Each of the molecules acquire another phosphate group and stores some energy in two molecules of the electron carrier, NADH. (There is now a phosphate group on each end of the two 3-carbon molecules). 5. Then, each 3-carbon molecule donates both of its phosphate groups to ADP molecules, which produce ATP molecules. (1 phosphate group creates 1 ADP molecule, which creates 1 ATP molecule. So there is now 2 ATP molecuels in each of the two 3-carbon molecules, making 4 in total). In total, 4 ATP are produced. Recall that 2 ATP were used to start the reactions. The net yield is 2 ATP. 6.The 3-carbon molecules now do not have any phosphate groups. They are not 3-carbon molecules of pyruvate.

What are the starting materials and end products of glycolysis?

Starting materials: -A 6-carbon glucose molecule -2 ATP + 2 phosphate groups -2 NAD+ Ending products: -Yield of 2 ATP (4 total, but yield is only 2) -2 electron-carrying NADH molecules -2 pyruvate molecules (3-carbon molecules)

Ch. 4

The Energy of Life

Nucleus

The nucleus contains DNA, which specifies the "recipe" for every protein a cell can make. The most important organelle in most eukaryotic cells.

Fluid mosaic

The cell membrane is often called a fluid mosaic because diverse molecules (the pieces of the "mosaic") drift freely among the phospholipids. Sterols, including cholesterol in animal cells membranes, maintain the membrane's fluidity.

Chloroplast

The chloroplast is the site of photosynthesis in eukaryotic cells. Eukaryotes that carry out photosynthesis have chloroplasts, organelles that use sunlight to produce food for the cell. The food then travels to the mitochondria, which extract the energy used for cellular processes. Each chloroplast contains multiple membrane layers.

ATP

The covalent bonds of adenosine triphosphate, a molecule commonly known as ATP, temporarily store energy released in chemical reactions - such as the digestion of an energy bar - just long enough to power muscle contractions and all other reactions that require energy input. ATP is a type of nucleotide. Its components are the nitrogen-containing base adenine, the five-carbon sugar ribose, and three phosphate groups (PO4). ATP is the cellular energy currency. A cell can use respiration to rebuild its pool of ATP. ATP hydrolysis is coupled with energy-requiring reactions: a. ATP energizes target molecule, making it more likely to bond with other molecules. (e.g. ATP provides the energy to build large molecules out of small subunits) b. ATP donates a phosphate group that changes the shape of the target molecule. (e.g. phosphate group changes shape of membrane transport protein) All cells rely on the potential energy stored in ATP to power chemical reactions. Removing the endmost phosphate group by hydrolysis releases the potential energy stored in ATP. The cell uses this energy to do work. ATP must then be reformed. Mitochondria release energy from food, producing ATP from ADP. In eukaryotic cells, organelles called mitochondria produce most of a cell's ATP. The mitochondrion uses the potential energy in the bonds of one glucose molecule to generate dozens of ATP molecules in cellular respiration. Not surprisingly, the most energy-hungry cells, such as those in the muscles and brain, also contain the most mitochondria.

Cytoskeleton (and its 3 major components)

The cytoskeleton is a network of protein tracks and tubules. It has several functions: -Structural support -Aids in cell division -Organelle transport -Cell movement The cytoskeleton has three major components: 1. Microfilaments 2. Intermediate filaments 3. Microtubules

Oxidation

The loss of electrons from a molecule, atom, or ion. Oxidation reactions, such as the breakdown of glucose to carbon dioxide and water, release energy as they degrade complex molecules into simpler products Oxidation is the loss of electrons from an atom or molecule; these reactions release energy.

The mitochondria contains both ___ and ___.

The mitochondria contains both DNA and ribosomes.

Kilocalorie

The most common unit for measuring the energy content of food is the kilocalorie (kcal). 1 kilocalorie = 1,000 calories 1 kilocalorie = 1 food calorie (food calories are calories with a capital C)

Aerobic Respiration

The process of using glucose and oxygen (O2) to produce ATP is called aerobic respiration (reverse of photosynthesis). C6,H12,O6+6O2 --> 6CO2+6H20+36ATP (Glucose + Oxygen --> Carbon dioxide + Water + ATP) Like photosynthesis, respiration is an oxidation-reduction reaction. Plants, animals, and many microbes, especially those in oxygen (O2) rich environments, use aerobic respiration. The pathways of aerobic respiration oxidize (remove electrons from) glucose and reduce (add electrons to) O2. Aerobic cellular respiration requires organisms to acquire oxygen (O2) and get rid of carbon dioxide (CO2).

Group/Stage 2: Krebs Cycle

The pyruvate molecules then enter a mitochondrion, where they are disassembled into carbon dioxide molecules during the Krebs cycle. Additional reactions, including the Krebs cycle, oxidize the pyruvate and release CO2. Enzymes rearrange and atoms and electrons to ATP, NADH, and another electron carrier molecule - FADH2. By the time the Krebs cycle is complete, the carbon atoms that made up the glucose are gone - liberated as carbon dioxide (CO2). The cell has generated a few molecules of ATP, but most of the potential energy from glucose now lingers in the high-energy electron carrier, NADH and FADH2. The cells use them to generate more ATP (through the electron transport chain)

The reactions of Krebs cycle and the electron transport chain require ____. These reactions yield much more ___ than glycolysis.

The reactions of Krebs cycle and the electron transport chain require oxygen gas. These reactions yield much more ATP than glycolysis.

Active site

The region to which substrates bind

Matrix (i.e the mitochondrial matrix)

The space within the inner membrane is the mitochondrial matrix, which houses the reactions of the Krebs cycle. The mitochondrial matrix is the fluid encolsed within the inner membrane.

Concentration gradient

The term gradient describes any such difference between two neighboring regions. In a concentration gradient, a solute is more concentrated in one region than in a neighboring region. For example, you can immediately see a concentration gradient when you first place a tea bag in a cup of hot water: near the tea bag, there are many more brown tea molecules than elsewhere in the cup.

The total amount of energy in any object is...?

The total amount of energy in any object is the sum of energy's two forms: potential and kinetic. Potential energy in the chemical bonds of food is converted to kinetic energy as muscles push a cyclist to the top of a hill. The potential energy of gravity provides a free ride down the hill by conversion to kinetic energy.

Golgi apparatus

The vesicles leaving the rough ER fuse with the Golgi apparatus—a stack of membrane sacs that acts as a "processing center". The proteins leave the Golgi in vesicles, which fuse with the cell membrane, expelling their contents. Other vesicles leaving the Golgi carry digestive enzymes. These vesicles fuse with lysosomes, where cellular digestion occurs.

Metabolism

The word metabolism encompasses all of these chemical reactions in cells, including those that build new molecules and those that break down existing ones. Metabolism includes all chemical reactions in cells, including those that build new molecules and those that break down existing molecules. Each rxn rearranges atoms into new compounds and either absorbs or releases energy

Intermediate Filaments

These filaments, are more stable (strongly bound) than actin filaments. They function in the maintenance of cell-shape by bearing tension

Microfilaments

Thinnest filaments of the cytoskeleton. They are composed of linear polymers of actin subunits, and generate force by elongation at one end of the filament coupled with shrinkage at the other, causing net movement of the intervening strand. They also anchor one cell to another.

What happens in between Glycolysis and the Krebs cycle? Where does this occur?

This all occurs in the matrix The two pyruvate molecules produced in glycolysis undergo an oxidation reaction as they enter the mitochondrion. A carbon atom is stripped from each pyruvate (making it a 2-carbon molecule), and leaves the cell as a carbon dioxide molecule (2 carbon dioxide molecules leave, one from each). At the same time, NAD+ is reduced to NADH (one NAD+ / NADH for each of the 2 pyruvates). Through this process, each pyruvate molecule is converted to an acetyl CoA molecule. (2-carbon molecule, 2 of them in total). Each acetyl CoA molecule then enters the Krebs cycle.

What happens in the Electron Transport Chain? Where does this take place?

This takes place in the mitochondria (intermembrane compartment) Beginning: NADH and FADH2 donate their electrons to the electron transport chain, where energy from the electrons is used to produce many ATP. (1)Energy-rich electrons removed from NADH and FADH2 slowly release their energy as they are transferred along the proteins of the electron transport chain. (2) Membrane-bound enzymes use the energy to pump protons (H+) from the matrix to the intermembrane compartment, establishing a gradient across the inner mitochondrial membrane. (Slide says: as the electrons travel through the transport chain, carrier molecules use the potential energy of the electrons to transport hydrogen ions into the intermembrane compartment). (3) The electrons are eventually dumped on oxygen (O2), producing H2) as a waste product. (Slide says: At the end of the transport chain, electrons are donated to an oxygen (O2) atom, which combines with hydrogens (H+) to form water (H2O) [the formula is 1/2 O2 + 2H+] ). (4) Meanwhile, the protons (hydrogen ions) flow down their concentration gradient from the intermembrane compartment into the matrix through a channel in ATP synthase. This action releases energy, which ATP syntahse uses to produce ATP.

*6.2* Cellular respiration include ____ (how many) main processes.

Three

Tight junction

Tight junctions fuse the membranes of adjacent animal cells together, preventing substances from flowing between the cells

Vesicles

Vesicles transport materials inside the cell. Proteins synthesized at the RER will be secreted from the cell. The proteins exit the organelle in bubbles of membrane called vesicles. Proteins and lipids are packed into vesicles from both rough and smooth ER to the Golgi apparatus, which are then processed and packaged for export out of the cell to the cell membrane. At the cell membrane, proteins and lipids are released from the cell when vesicles fuse with the cell membrane.

What does the symbol H2O (where the 2 is small and under the H) represent?

Water

isotonic solutions, hypotonic solutions, and hypertonic solutions.

Water moves toward high solute concentrations as it moves down its concentration gradient. iso = same. There is the same amount of water going into the cell as there is water leaving the cell. hypo = less. There is less water coming out of the cell than water going into the cell. hyper = more. There is more water coming out of the cell than there is water going into the cell.

In the absence of oxygen, a cell can re-create NAD+ by another pathway, called ____.

fermentation

Glycolysis splits ____.

glucose

NADH and FADH2

high-energy electron carrier molecules

Energy transformations are _____.

inefficient

Active transport _____ energy

requires

Enzymes _____ biochemical reactions

speed

Large substances enter or leave cells in ____.

vesicles