Biology chapter 5-8

What is oxidation-reduction reactions?

-Transfer of electrons from one molecule to another. -They're always coupled together -called redox reactions

What are the names and functions of major organelles of the Endomembrane system of eukaryotic cells?

1. The nucleus stores the cells genetic information and is the site of transcription. 2. The endoplasmic reticulum is the organelle in which proteins and lipids are synthesized. 3. The Golgi apparatus modifies proteins and lipids produced by the ER and acts as a sorting station . 4. Rhizomes contains enzymes that break down macromolecules such as proteins, nucleic acid's , lipids, and complex carbohydrate

How can the reactions of glycolysis be subdivided into preparatory cleavage and payoff phases?

1. The preparatory phase prepares glucose for the next two phases by the addition of two phosphate groups to glucose. Two molecules of ATP also are consumed. 2. The cleavage phase is when the 6 carbon molecule is split into two 3 carbon molecules. 3.) The pay off stage is when ATP and the electron carrier NADH are produce. this phase ends with the production of two molecules of pyruvate.

Summarize each stage of cellular respiration.

1.) Glycolysis-Glucose is the starting molecule. Glucose is patially broken down to produce pyruvate and energy in the form of ATP + reduced electron carriers which is released. 2.) Pyruvate oxidation- pyruvate ( the break down product of glucose from stage 1) is converted to Acetyl Co A and carbon dioxide and electron carriers are produced. 3.) Citric Acid cycle- Acetyl Co A is broken down and carbon dioxide, ATP, and reduced electron carriers are produced. 4.) Oxidative phosphorylation-electron carriers generate in stages 1-3 donate their electrons to and ETC. This chain transfers electrons along a series of membrane associated proteins to a final electron acceptor and in the process harnesses the energy of the electrons to produce a large amount of ATP. in aerobic respiration oxygen is the final electron acceptor or so it is consumed and water is produced

What is the role of the Golgi apparatus in introducing chemical modifications to proteins and directing them to their final cellular or extracellular location?

1.) it further modifies proteins and lipids produced by the ER. 2.) it acts as a Sorting station as these proteins and lipids move to their final destinations. 3.) it is the site of synthesis of most of the cells carbohydrates.

What are the two different ways in which ATP is generated in cellular respiration?

ATP is generated by substrate level phosphorylation and oxidative phosphorylation.

A cells membrane contributes to homeostasis by?

Acting as a selective barrier

Passive transport or active transport require energy?

Active transport, requires (ATP)

Summarize the yield of ATP and electron carriers produced by one turn of the citric acid cycle.

After one turn of the citric acid cycle 3 molecules of NADH, 1 molecule of FADH2, 2 carbon dioxide molecules , 1 molecule of ATP is produced.

Why does active transport of molecules across a membrane require ATP?

An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration.

At the end of glycolysis but before the subsequent stages in cellular respiration which molecules contain some of the chemical energy held in the original glucose molecule?

At the end of glycolysis the energy in the original glucose molecule is contained in pyruvate ATP and NADH.

At the end of pyruvate oxidation but before the subsequent stages of cellular respiration which molecules contain the energy held in the original glucose molecules?

At the end of pyruvate oxidation the energy in their original glucose molecule is contained in Acetyl-CO A and NADH.

At the end of citric acid cycle but before the subsequent stages of cellular respiration which molecule contain the energy held in the original glucose molecules?

At the end of the citric Acid cycle the energy in the original glucose molecule is contained in ATP, NADH and FADH2.

Which of the structures are part of the Endomembrane system ? A. Peroxisones , B. The nuclear envelope C. Mitochondria D. Chloroplasts

B. Nuclear envelope

Why does cholesterol increase membrane fluidity (at low temperatures) ?

Because it prevents phospholipids from packing tightly with other phospholipids

Why does cholesterol decrease membrane fluidity?

Because of the interactions of the rigid ring structure of cholesterol with the phospholipid fatty acid tails reduces the mobility of the phospholipids.

How does other monosaccharides become intermediate of glycolysis?

Because the glucose molecules released during digestion directly enters glycolysis. The sugars also enter glycolysis, but they are not glucose, instead they are converted into intermediates of glycolysis that come later in the pathway.

Are mitochondria present in plants, animal cells or both?

Both

What are three similarities between mitochondria in chloroplast?

Both mitochondria and chloroplasts are organelles involved in generating energy for the cells in which they live; The structure of both organelle types includes an inner and an outer membrane. They are both found in eukaryotic cells.

How is a carrier protein different from a channel protein?

Carriers undergo a conformational change.

What does Cholesterol help maintain?

Cholesterol helps maintain a consistent state of membrane fluidity by preventing dramatic transition from a fluid to a solid-state.

An amphipatic molecule is one that ?

Contains both polar and non polar regions

The random movement of molecules within a solution is referred to as?

Diffusion

Predict the net direction of movement of molecules via diffusion in a concentration gradient

Diffusion results in net movement of molecules from an area of higher concentration to an area of lower concentration.

What is the summarization of cellular respiration as the breakdown of sugar molecules in the presence of oxygen to produce carbon dioxide and water.

During cellular respiration sugar is broken down to CO2 and in the process, ATP is made that can then be used for cellular work.

What happens during ethanol fermentation

During ethanol fermentation pyruvate releases carbon dioxide to form acetaldehyde to produce ethanol and NAD+.

What happens during lactic acid fermentation

During lactic acid fermentation electrons from NADH are transferred to pyruvate to produce lactic acid and NAD+

What is ethanol fermentation

Ethanol fermentation occurs in plants and fungi.

What are the kinds of membrane enclosed organelles contained in eukaryotic cells?

Eukaryotes cells have plasma membrane, Cytoplasm, ribosomes, Endoplasmic reticulum, Golgi apparatus , chloroplasts and mitochondria

Where are nucleus found?

Eukaryotic cells

The relative concentrations of solute and water are not equal on both sides of the membrane. True or false

False. They are equal.

What is the difference between the potential energy in the bonds of fuel molecules and in the products carbon and water?

Fuel molecules have a large amount of potential energy in their chemical bonds, whereas molecules such as carbon dioxide and water have less potential energy in their bonds.

What are the two forms glucose can be stored in?

GLYCOGEN (IN ANIMALS), STARCH(IN PLANTS).

Which molecules can easily diffuse across a plasma membrane ?

Gases like O2 and CO2

Where is plasma membrane found and what is it made of?

In all cells, made of phospholipids and proteins (Bilayer).

How does the substrate level phosphorylation produce ATP during glycolysis?

In glycolysis ATP is formed By direct transfer of a phosphate group to ADP from a substrate.

What is the difference between the two ways ATP is generated?

In substate-level phosphoylation ATP is generated in which a phosphate group is transferred to ADP from an organic molecule , which acts as a phosphate donor or substrate. Whereas in oxidative phosphorylation ATP is generated by a set of metabolic reactions that occur by passing electrons along an electron transport chain, which drive the synthesis of ATP

How is pyruvate processed differently in the absence of oxygen?

In the absence of oxygen, pyruvate can be broken down by fermentation

What are the two different metabolic pathways that pyruvate can enter?

In the first pathway pyruvate is converted to acetyl-COA, which is the starting substrate got the citric acid cycle. The second pathway is fermentation, a reaction that happens without energy.

What are two ways proteins associate with membranes?

Integral membranes, peripheral membranes

Describe the cellular location of the citric acid cycle with reference to the other phases of cellular respiration.

Like the synthesis of acetyl-CO A, the citric acid cycle takes place in the mitochondrial matrix.

Describe the kinds of structures that forms spontaneously when phospholipids are placed in an aqueous environment ?

Lipids have properties that allow them to form a barrier in an aqueous environment. In an aqueous environment amphipatic molecules such as phospholipid behave in an interesting way, they spontaneously arrange themselves into various structures in which polar head groups on the outside interact with water in the non-polar tail groups come together on the inside away from the water.

What are micelles?

Lipids with bulky heads and a single hydrophobic fatty acid tail are wedge-shaped and packed into spherical structures.

What are the bilayers made of?

Lipids with less bulky head groups, two hydrophobic tails are roughly rectangular.

A cell has a mutation that prevents it from breaking down unwanted proteins present in vesicles. Which cellular structure is most likely to be disrupted by this mutation?

Lysosomes

What is the role of lysosomes in recycling cellular components?

Lysosomes degrade damaged or unneeded macromolecules. It is a specialized vesicle from the Golgi apparatus, used to break down macromolecules. It is filled with enzymes. And Is only in plant cells

How does muscle tissue generate ATP during short term and long term exercise?

Muscle tissue generate ATP during short term exercise by converting stored glycogen to glucose. Glucose is rapidly broken down anaerobically to pyruvate, which then feeds into the lactic acid fermentation pathway. During long-term exercise, the liver releases glucose into the blood which is taken up by muscle cells and oxidize to produce ATP. The end result is the production of more ATP than the fermentation pathway can produce.

What is the importance of fermentation as a mechanism for providing NAD+ for glycolysis?

NAD+ molecules that are reduce during glycolysis are oxidized when lactic acid or ethanol is formed. ALSO The purpose of the extra reactions in fermentation, then, is to regenerate the electron carrier NAD+ from the NADH produced in glycolysis.

What are the sources of electrons used by the electron transport chain?

NADH and FADH2

What is oxidative phosphorylation?

Occurs in stage four of cellular respiration. Uses energy released by the electron transport chain to power ATP synthesis.

What is an oxidation reduction reaction

Oxidation reduction reactions are used to store or release chemical energy.

Animals breathe in air that contains more oxygen than the air they breathe out where is oxygen consumed?

Oxygen is consumed in cellular respiration. Oxygen is the final electron acceptor in the electron transport chain and is converted to water.

What is the difference between passive and active transport?

Passive transport work though diffusion , facilitated diffusion, move ions from high concentration to lower. Active transport work through concentration gradient , moves ions from low concentration to high

What are integral membrane proteins ?

Permanently associated with the membrane and cannot be removed without destroying the membrane itself. They have both hydrophilic and hydrophobic regions

Does prokaryotes have internal membrane enclosed structures and a nucleus?

Prokaryotes lack a nucleus and extensive internal compartmentalization. Meaning that they do not have a nucleus and do not have internal membrane enclosed structures Their internal fluid is called cytosol. It's genetic material consist of a large DNA molecule compacted in an area called nucleoid region.

Compare the organization, degree of compartmentalization, and size of prokaryotic and eukaryotic cells.

Prokaryotic cells lack a nucleus and extensive internal compartmentalization. They contain plasmids that carry additional genes that can be transferred to other bacteria. Prokaryotic cells are also small (usually 1-2 micrometers in diameter or smaller). Because of their small size, they have a large surface-area-to-volume ratio and thus are able to absorb nutrients from the environment to meet their metabolic needs. Eukaryotic cells have a nucleus and specialized internal structures called organelles. They are 10 times larger in diameter and 1,000 times larger in volume than a prokaryotic cell.

How many different organic molecules can be synthesized from intermediates of the citric acid cycle?

Pyruvate is the starting point for the synthesis of sugars and the amino acid alanine; acetate is the starting point for the synthesis of the cells lipids; oxaloacetate is modified to form different amino acids and pyrimidine bases ; a(alpha)-ketoglutarate is modified to form other amino acids.

Identify the products of pyruvate oxidation within the context of cellular respiration.

Pyruvate oxidation converts pyruvate to acetyl CO A, producing 2NADH and 2 carbon dioxide.

Describe the cellular location of pyruvate oxidation with reference to the locations of the other phases of cellular respiration.

Pyruvate oxidation is the first step that takes place inside the mitochondria. Pyruvate is transported into the mitochondrial matrix where is then converted into Acetyl-COA.

contrast the two types of ER

Rough ER is stubbed with ribosomes, synthesizes transmembrane proteins, they are cells that secrete large quantities of protein, Main function is to produce protein. Smooth ER lacks ribosomes, primary site of lipid synthesis, has enzymes within it that convert cholesterol into steroid hormones.

How are the rough ER and smooth ER similar?

Same type of membrane (Endomembrane) Both are connected to the nuclear envelope

Which types of fat contain saturated fatty acid and which type contain unsaturated fatty acids?

Saturated = solid at room temperature; ex butter, and other animal fats. Unsaturated = liquid; plants (and fish ) oils contain unsaturated fatty acid's and are liquids at room temperature

Predict the effects of saturated versus unsaturated phospholipid structures

Saturated phospholipids lack double bonds, resulting in phospholipids with a straight structure that favors tight packing. Unsaturated phospholipids have one or more double bonds that introduce kinks in the phospholipids, reducing the tightness of packing.

Explain the manner in which a protein will be associated with the plasma membrane, given the proteins function.

Some act as transporters meaning they move ions or other molecules across the membrane. Some act as receptors which allow the cell to receive signals from the environment. Others are enzymes that catalyze chemical reactions or anchors that attach to other proteins and help to maintain cell structure in shape.

Describe how membrane pumps like the sodium potassium pump, maintain isotonicity.

Some proteins act as pumps using energy directly to move a substance into or out of the cell. It helps keep the inside of the cell isotonic with extracellular fluid.

What is the nucleus?

Storage of genetic material(DNA); RNA synthesis.

What is substrate level phosphorylation?

Substrate level phosphorylation is the direct transfer of a phosphate group from an organic substrate to ADP by an enzyme (usually a kinase). This process occurs during glycolysis and the citric acid cycle. Substrate level phosphorylation generates much less ATP during cellular respiration than oxidative phosphorylation.

What are peripheral membrane proteins?

Temporarily associated with the membrane and can easily be experimentally separated. They are mostly hydrophilic and interact with the polar heads of the lipid bilayer, or the hydrophilic regions or integral membrane proteins.

What does the endoplasmic reticulum do?

The ER produces and transports many of the proteins and lipids used inside and out of the cells.

Why is the breakdown of glucose in the presence of oxygen to produce carbon dioxide and water an example of an oxidation reduction reaction?

The carbon atoms in glucose are oxidized because they go from sharing electrons equally in the carbon carbon bonds to partially losing electrons in the Carbon oxygen bonds of the carbon dioxide molecule. Also for oxygen , which is reduced in the same reaction. the oxygen atom go from sharing electrons equally to partially gaining electrons when water is formed

What is fermentation?

The catabolic process that allows glycolysis to proceed in the absence of oxygen.

What is the role of the cell wall in maintaining the size and shape of plant, fungal, and bacterial cells?

The cell wall provide structural support and protection for the cell. Cells can use active transport to maintain the intracellular solute concentration so that it equals the extracellular solute concentration. The cell wall also provides a rigid structure surrounding the cell membrane.

Describe the role of chloroplasts in plant cells

The chloroplasts captures the energy of sunlight to synthesize simple sugars.

Explain the role of electron carriers in providing electrons to the electron transport chain.

The electron carriers acts as ubers in delivering electrons to the electron transport chain. NADH and FADH2 transfers electrons to the ETC.

Determine how the size and the electrical charge of membrane proteins influence their interactions with the hydrophobic and polar structures of membrane phospholipids

The hydrophobic interior of the lipid bilayer prevents ions and charge polar molecules from moving across it. Macromolecule such as proteins and polysaccharides or too large to cross the plasma membrane on their own. Small uncharged polar molecules such as water are able to move through the lipid bilayer to a very limited extent.

What is oxidation?

The loss of electrons

Describe the role of mitochondria in plants and animals

The mitochondria convert chemical compounds to ATP. It also acts as a digestive system which takes in nutrients, breaks them down and creates energy rich molecules for the cell .

How does the movement of electrons along the electron transport chain lead to the generation of a proton gradient?

The movement of electrons along the electron transport chain in the inner mitochondrial membrane is coupled to the transfer of protons through several enzyme complexes and electron carriers. As electrons pass through the complexes, protons are pumped into the inter-membrane space. this creates a concentration and charge gradient providing a source of potential energy that is used to drive the synthesis of ATP

What is the roles of the nuclear envelope in regulating which molecules move in and out of the nucleus?

The nuclear envelope consist of two membranes, inner and outer. The nuclear envelope has nuclear pores that allows molecules to move in out of the nucleus. The nuclear envelope protects the cells genetic material from the chemical reactions that takes place outside of the nucleus.

How do lipids with hydrophilic and hydrophobic regions behave in an aqueous environment?

The polar hydrophilic head groups readily interacts with the polar molecules. While the non polar hydrophobic tail does not readily interact with water but instead interact with other non-polar tail groups or hydrophobic molecules.

Predict the effects of the presence of Cholesterol, on the fluidity of a membrane?

The presence of Cholesterol increases or decreases membrane fluidity depending on the temperature.

How is a proton gradient used to generate ATP?

The protons accumulated in the inter-membrane space can not passively diffuse across the membrane, so they diffuse through a transport channel called ATP synthase. This enzyme is composed of two subunits: Fo( the channel through which protons flow) and F1( the catalytic unit that synthesizes ATP. Proton flow through the channel causes it to rotate which converts the energy of the proton gradient into mechanical rotational energy (kinetic energy). The rotation of Fo subunit leads to rotation of the F1 subunit. Rotation causes conformational changes in the F1 subunit that allow it to catalyze the synthesis of ATP from ADP and Pi.

For each of the following pairs of molecules indicate which member of the pair is reduced and which is oxidized and also which has more chemical energy and which has less chemical energy. NAD+/NADH; FAD/FADH2; CO2; C6H12O6.

The reduced molecules are NADH, FADH2, and C6H12O6. The oxidized molecules are NAD+, FAD, and CO2. The reduced form have more chemical energy than their corresponding oxidized form.

How is the citric acid cycle related to the completion of the oxidation of fuel molecules, starting from Acetyl -CO A?

The two carbon acetyl group of acetyl- CO A is transferred to a four carbon molecule of oxaloacetate to form the six carbon molecule citric acid.

How are passive and active transport similar?

They both use ion channels to move ions across the cell membrane, in or out of the cell.

What are the roles of lipids and proteins in maintaining the selective permeability of membranes?

They help prevent charge molecules and ions from diffusing freely into the cell. Proteins help transport larger molecules by acting as channels and carriers that transport molecules in and out of the cell.

Describe active transport of molecules across a biological membrane

Transporting molecules require energy, either directly or indirectly. During active transport cells move substances through transport proteins embedded in the cell membrane.

True or false in both fermentation pathways NADH is oxidized to NAD+.

True

True or false is excess glucose stored as glycogen in animals and starch in plants?

True

True or false. The process Of glycolysis is a chemical pathway with 10 reactions?

True

What is the net production from glycolysis of ATP and NADH.

Two molecules of ATP and two molecules of NADH.

How does catabolism of glucose involves oxidation-reduction reactions?

When some fuel molecules such as glucose are catabolized some of the steps are oxidation reactions. These oxidations are coupled with the reduction of electron carrier molecules. NAD+ +2e-+H+-> NADH.... FAD +2e- +2H+-> FADH2 And also flipped around. There electron carries molecules act as ubers.

How does linking glucose together into polymers of glycogen or starch alleviate situations of excess glucose

When the blood glucose level is high , glucose molecules that are not consumed by glycolysis are linked together to form glycogen in liver and muscle. glycogen stored in the muscle is used to provide ATP for muscle contraction.

Bread making involves ethanol fermentation and typically uses East sugar flour and water. Why are yeast and sugar used?

Yeast cells are eukaryotes. In bread making yeast can use sugar as a food source for ethanol fermentation. The carbon dioxide produced in the process causes the bread to rise. The ethanol is removed in the baking process.

What is the plasma membrane?

acts as a selective barrier, seperate the inside of the cell from the outside.

What is reduction?

gain of electrons

RNA molecules are transported from the nucleus to the cytoplasm in eukaryotes through ?

nuclear pore complexes

What is lactic acid fermentation?

occurs in animal, bacteria. Requires no oxygen

How much ATP does substrate- level phosphorylation and oxidative phosphorylation produce?

small amount (12%), large amount(88%)

In cellular respiration, what is oxidized or burned?

sugar (C6H12O6) is burned, oxidized down to CO2