BIOL EXAM2

Proteins

Made of C, H, O with N, S, P and are polymers of amino acids. Have carboxyl and amino (NH3) groups. Function: Structural: skeletal support Movement: muscle Cell membrane components: receptors, pathways for crossing membranes, identification, enzymes. Various other functions

CARBOHYDRATES

Made of C, H, O. General formula of (C1H2O1)n Types of carbohydrates: Monosaccharides (simple sugars) Disaccharides (two sugars) Polysaccharides (many sugars) Function: varies, but is the most important energy molecule in living things

Which of the following statements regarding membrane protein function is false?

Membrane proteins transfer genetic information to the cytoplasm

Given the relatively modest number of calories burned by anything but the most vigorous activities, why can people consume over 2,000 kilocalories a day, yet maintain a healthy body weight?

Most of the energy consumed in food is spent maintaining the body's functions, so only a fraction of food energy needs to be burned in exercise.

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

Enzymes

(proteins that act as biological catalysts) are involved in chemical reactions.

Major differences between prokaryotes and eukaryotes

-DNA -Types of reproduction: binary fission vs mitosis. -Eukaryotic cells are the cells of multicellular organisms (sexual reproduction). -Eukaryotic cells have membrane-bound organelles.

Movement across membranes

1. Simple diffusion (channels). 2. Facilitated transport ("helper" proteins). 3. Active transport (pumping proteins). 4. Endocytosis: phagocytosis or pinocytosis. 5. Exocytosis

PHOTOSYNTHESIS

6CO2 + 6HOH ------> C6H1206 + 6O2 Energy input from the sun (solar energy). Requires special plant pigment: Chlorophyll The key: ENERGIZED ELECTRONS

Movement of matter

Brownian movement Simple diffusion

What is the correct general equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy

The overall equation for the cellular respiration of glucose is

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy.

Organic molecules

Carbohydrates Lipids (fats and oils) Proteins Nucleic Acids

Cellular Respiration Equation

Combustion of Glucose to carbon dioxide and water. Releases Free Energy. 686 kcal of energy released: about 263 kcal trapped in ATP and 423 lost as heat.

Reactions: organic molecules

Condensation (dehydration) Hydrolysis anabolic (build up) catabolic (break down) endergonic (energy consuming) exergonic (energy releasing)

Nucleic acids

Deoxyribonucleic acid (DNA) which is the molecule that stores genetic information. Ribonucleic acid (RNA) which includes different types that do the work of using DNA information to make proteins. RNA includes messenger RNA, Ribosomal RNA and transfer RNA. BOTH ARE CHAINS OF NUCELOTIDES.

Which of the following statements regarding diffusion is false?

Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated.

Which of the following best describes the electron transport chain?

Electrons pass from one carrier to another, releasing a little energy at each step

Glycolsys

Glucose (6-C sugar) is broken down into two pyruvates (3-C sugars).

Movement of matter

Hypotonic, Isotonic, Hypertonic, and Permeability, Osmosis.

DNA, deoxyribonucleic acid

Is double stranded. Nitrogenous bases are guanine, adenine, cytosine, and thymine (no uracil). Is the hereditary storage molecule.

RNA, ribonucleic acid

Is single stranded. Nitrogenous bases are guanine, adenine, cytosine, and uracil (no thymine). Is the "work" molecule. Different types of RNA: messenger, ribosomal, and transfer

ENERGY

Laws of thermodynamics First law: energy cannot be created or destroyed; it is transferred. Second law: energy transfers increase entropy (= disorder). Living things must function within the bounds of these laws.

In fermentation, ________ is ________.

NADH; oxidized

Which of the following statements regarding the movement of electrons during cellular respiration is true?

O2 is reduced when it accepts electrons and forms water.

Facultative aerobes

Oxygen present: cellular respiration Oxygen absent: Incomplete glycolysis results in lactic acid or ethanol.

Obligatory aerobes

Oxygen present: cellular respiration Oxygen absent: death

Obligatory anaerobes

Oxygen present: death Oxygen absent: energy production

Cellular respiration is an example of __________.

an exergonic process

By-products of cellular respiration include

carbon dioxide and water.

Each turn of the citric acid cycle generates one ATP and ___ additional energy-rich molecules: __________.

four; 3 NADH and 1 FADH2

When a cell uses fatty acids for aerobic respiration, it first hydrolyzes fats to

glycerol and fatty acids.

Simple diffusion

matter moving down a concentration gradient.

Lungs are to breathing as _____ are to cellular respiration.

mitochondria

The electron transport chain is a series of electron carrier molecules. In eukaryotes, where can this structure be found?

mitochondria

An energy barrier

prevents the spontaneous breakdown of molecules in the cell.

Kreb's Cycle (Citric Acid Cycle)

pyruvate is completely broken down into carbon dioxide as high energy electrons are released and captured.

The end products of the citric acid cycle include all of the following except

pyruvate.

In eukaryotes, most of the high-energy electrons released from glucose by cell respiration _____.

reduce NAD+ to NADH, which then delivers them to the electron transport chain

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will _____.

remain standing upright

According to ________, energy cannot be created or destroyed.

the first law of thermodynamics

Oxidative phosphorylation could not occur without glycolysis and the citric acid cycle, because _____.

these two stages supply the electrons needed for the electron transport chain

Electron Transport System (ETS):

uses high energy electrons to make ATPs. This is making of ATPs in the presence of oxygen. ATP is made during chemiosmosis, a process called OXIDATIVE PHOSPHORYLATION.

Protein Structure

Primary structure is the sequence of amino acids. Secondary structure is the alpha helix (and may lead to pleated sheeting). Tertiary structure is 3-D structure (may include folding). Quaternary structure is combining of two or more molecules together

Three steps of Cellular Respiration: glycolysis, Kreb's cycle, ETS

Purpose is to release and capture free energy in: ATP molecules High energy electrons on electron transport molecules to take to the ETS

What is the purpose of embedding the electron transport chain in the membrane of a cell?

The membrane is impermeable to H+.

According to the second law of thermodynamics, which of the following is true?

The ordering of one system depends on the disordering of another.

What is the ultimate fate of the electrons that are stripped from glucose during cellular respiration?

They are used to form water.

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

Brownian movement

constant, random movement because all matter has energy.

Which of the following is a result of glycolysis?

conversion of glucose to two three-carbon compounds

The fluid mosaic model describes the plasma membrane as consisting of

diverse proteins embedded in a phospholipid bilayer.

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy.

endergonic ... requires an input of

Which of the following options lists the stages in cellular respiration in the correct order?

glycolysis, the citric acid cycle, and oxidative phosphorylation

The mitochondrial cristae are an adaptation that

increases the space for more copies of the electron transport chain and ATP synthase complexes.

Light is _____ energy, which is converted by plants into molecules, which possess _____ energy.

kinetic ... chemical

When a car engine burns gasoline, the results of the reaction are similar to when cells burn glucose. Both reactions release carbon dioxide and water. In cells, the chemical energy in food is converted to ATP and heat. In a moving car, the chemical energy in gasoline is converted to _____.

kinetic energy and heat

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion

Bacteria that are unable to survive in the presence of oxygen are called

obligate anaerobes.

The diffusion of water across a selectively permeable membrane is called __________.

osmosis

You are adrift in the Atlantic Ocean and, being thirsty, drink the surrounding seawater. As a result,

you dehydrate yourself.

Which statement regarding enzyme function is true?

Excessive salt ions can cause an enzyme to denature.

What is the basic difference between exergonic and endergonic reactions?

Exergonic reactions release energy; endergonic reactions absorb it.

Which of the following statements regarding food is false?

Food provides the raw materials for biosynthetic pathways that can produce sugar by a process that is the exact opposite of glycolysis.

LIPIDS

Formed of C, H, O with many H. Have the acidic functional group COOH (carboxyl group). Function: cell and other membranes Plants: primarily cell and other membranes, protection against desiccation. Animals: energy storage, lubrication of some vertebrates (hair, feathers), insulation, cushioning.

Cellular Respiration

GLYCOLYSIS KREB'S CYCLE (CITRIC ACID CYCLE) ELECTRON TRANSPORT

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?

Water will leave the balloon.

During enzymatic reactions, substrates are converted to products. A property of enzymes that facilitates this reaction is that they are catalysts and therefore _____.

change the rate of a reaction without being consumed by the reaction