Exam 2 study guide

The surface area: volume ratio, and the effect it has on cell size?

The smaller the cell the higher surface area to volume ratio (SA:V)

what is Surface area?

volume ratio allows all processes at the plasma membrane to occur more efficiently. 

How do you recognize structures with high SA:V ratio

Structures with a high SA:V ratio are small, thin, or folded, giving them more surface area making them more efficient for exchange of gases, nutrients, and waste

• The similarities between prokaryotic and eukaryotic cells

Plasma membrane, DNA, and Ribosomes (organelle which makes proteins)

Eukaryotic cells

Nucleus, Membrane bound organelles, and much larger

Prokaryotic cells

No nucleus, No membrane bound organelles, and Much smaller and simpler

• The similarities between animal and plant cells

Nucleus → Nuclear envelope, Nucleolus, and Chromatin., Cytoskeleton → Microtubule and Microfilament, Peroxisome, Plasma membrane, Mitochondrion, Golgi apparatus, Smooth and Rough endoplasmic reticulum (ER)

Animal Cells

No cell wall, No chloroplasts, and Small temporary vacuoles, Intermediate filament, Lysosomes, Centrosome with pair of centrioles 

Plant Cells

Cell wall, Chloroplasts, Large central vacuoles, No intermediate filament, No Centrosome with pair of centrioles, No lysosomes  

The structure of a lipid bilayer

The top/head part of a lipid bilayer is hydrophilic while the bottom/tail part is hydrophobic.

what is the significance of the lipid bilayer structure in terms of water?

Significance is that the bilayer lets the cell control water flow and protects it from the outside watery environment and controls how water and dissolved substances enter or leave the cell.

Nucleus

Contains and protects the cell’s DNA; site of DNA replication and transcription

Nucleolus

Produces ribosomes

Ribosome

Organelle made primarily of RNA and protein

Rough endoplasmic reticulum

Has ribosomes on surface, site of synthesis and initial modification of proteins that will be secreted or used in other organelles

Smooth endoplasmic reticulum

NO ribosomes, site of synthesis and initial modification of NON-proteins that will be secreted or used in other organelles

Golgi

Responsible for the modifications and shipping of the protein and non protein products made in both the Rough and Smooth ER

Lysosome

Contain digestive enzymes: responsible for breaking down food and damaged organelles

Vacuole

Stores water, nutrients, and waste, Maintains water balance and cell shape, and helps with waste disposal and homeostasis

Transport vesicle

Carries proteins, lipids, and other molecules between organelles and helps move materials within the cell safely and efficiently

Plasma membrane

Controls what enters and leaves the cell (selectively permeable), Protects the cell and maintains homeostasis, and made of a phospholipid bilayer with embedded proteins

Mitochondria

Found in both plant and animal cells; site of most of cellular respiration, which generates the majority of a cell's ATP

Chloroplast

Found only in plant cells; site of photosynthesis

Microtubule

Can be rapidly assembled and disassembled; form the miotic spindle and highways for vesicle traffic

Intermediate filament

Anchor organelles in place, especially the nucleus

Microfilament

Form a layer immediately inside the plasma membrane, which reinforces the membrane and controls changes in its shape

Cilia/flagella

Organelles built around microtubules which allows cells to move

• Extracellular matrix (ECM)

A layer of glycoproteins outside the plasma membrane, which reinforces the plasma membrane and helps the cell sense the surrounding environment

The three types of cell-cell junction seen in animal cells

Tight junction, Anchoring junction, Gap junction

Tight junction

Joins cells into waterproof layers

Anchoring junction

 “steel rivet” which provides structural strength to layers of cells

Gap junction

Direct connection between cytoplasms of adjacent cells, but only large enough for ions or small molecules to fit through

what is the one cell junction seen in plant cells

Plasmodemata junction

Plasmodemata junction

Found only in plant cells; direct connection between cytoplasm of adjacent plant cells large enough for some macromolecules to fit through 

The endosymbiotic theory

The theory is that mitochondria and chloroplasts were once free living prokaryotic cells that were engulfed by a larger cell and became permanent organelles.

what is the evidence supporting the endosymbiotic theory

-Cells cannot make new mitochondria and chloroplasts; instead, these organelles replicate themselves. 

— Mitochondria and Chloroplasts have their own DNA and Ribosomes 

— The DNA and Ribosomes in these organelles are much more similar to prokaryotic DNA and Ribosomes than eukaryotic DNA and Ribosomes 

— There are close relatives of both mitochondria and chloroplasts still living as independent prokaryotic cells today 

** Essentially, mitochondria and chloroplasts act exactly like independent cells, except that they happen to live inside larger cells

• The cellular functions which take place at the plasma membrane

Diffusion of small nonpolar molecules

Transport (Active and Passive)

Allows specific ions or molecules to enter or exit the cell. (PM)

Enzymes

Some membrane proteins are enzymes, enzymes may be grouped to carry out sequential reactions (adjacent stages on an assembly line)(PM)

Integrin Proteins

Attach to the ECM (extracellular matrix) and cytoskeleton, helps support membrane, and can coordinate external and internal changes (PM)

Signal Reception

Signaling molecules bind to receptor proteins and receptor proteins relay the message by activating other molecules inside the cell(PM)

Cell-to-Cell Adhesion

Form intercellular junctions that attach adjacent cells(PM)

Cell-to-Cell Recognition

Serve as ID tags and may be recognized by membrane proteins of other cells

Diffusion

The movement of a substance from an area of High Concentration to an area of  Low Concentration (“with” or “down” the concentration gradient); Passive → Requires NO energy. Carried out by channel proteins

Active Transport

The movement of a substance from an area of Low Concentration to an area of High Concentration (“against” or “up” the concentration gradient); 

Active → Requires energy (usually ATP). Carried out by pump proteins

Endocytosis

The process in which a cell ingests a substance by engulfing it with the plasma membrane (requires energy, so technically a type of active transport)

Osmosis

Movement of water from an area of Low Solute Concentration to an area of High Solute Concentration

The types of molecules which can diffuse through the plasma membrane without the aid of proteins, and two key examples of this

Nonpolar and gases 

— Examples: Oxygen and Carbon dioxide

• The changes which plant and animal cells undergo based on different osmotic pressures

Turgid (normal), Flaccid, and Shriveled (plasmolyzed)

The role ATP plays within the cell, and the primary reaction through which it releases its energy

-ATP is the cells main energy source

— Hydrolysis; ATP turns into ADP which releases a large amount of chemical energy by breaking the bond between the 2nd and 3rd phosphate groups

The types of work the energy of ATP can be harnessed for in the cell

Chemical work

Transport work

Mechanical work

Chemical work

ATP transfer one of its phosphate groups to another molecule naking that molecule more reactive

Transport work

ATP transfers one of its phosphate groups to a pump protein, causing a change in the shape of the protein which moves a substance against its concentration gradient

Mechanical work

ATP transfers one of its phosphate groups to a motor protein, which causes a change in the shape of the protein which excerpts a mechanical force

• The function of enzymes in cells, and the reasons (that’s reasonS, plural) why that function is crucial

FunctionS: They allow chemical reactions to occur fast enough to sustain life and they give cells a way to regulate all of their chemical reactions (inhibit the enzyme → reaction stop)

• The function of enzymes in cells, and the reasons (that’s reasonS, plural) why that function is crucial

Crucial: Cells inhibit enzymes to avoid wasting resources making unnecessary products and Cells activate enzymes in order to ensure that all necessary products are being made

• The two ways in which enzymes can be inhibited

Competitive inhibition

Non competitive inhibition

Competitive inhibition

The inhibitor binds to the active site and directly blocks the substrate from entering

Non-Competitive Inhibition

 The inhibitor binds to the enzyme somewhere other than the active site, bending the active site out of shape so that it no longer fits the substrate

Concentration Gradient

The difference in the concentration of a substance between two areas

Solute

The substance that is dissolved in a solution

Solvent

The substance that dissolves the solute.

Solution

A homogeneous mixture of a solute and solvent

Hypotonic

A solution with a lower solute concentration and higher water concentration compared to another solution.

Isotonic

A solution with equal solute concentrations on both sides of a membrane.

Hypertonic

 A solution with a higher solute concentration and lower water concentration compared to another solution.

Endergonic

A chemical reaction that absorbs energy from its surroundings

Exergonic

A chemical reaction that releases energy to its surroundings.

Substrate

The reactant molecule that an enzyme acts upon in a chemical reaction.

Glycoprotein

A protein with carbohydrate chains attached that functions in cell recognition and signaling.

The basic chemical formula for cellular respiration

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

cellular respiration with all reactants

Reactants: anything that goes into a chemical reaction, the molecules that are used up.

• cellular respiration with all products

Anything that comes out of a chemical reaction, the molecules that are produced.

Oxidation

Loss of hydrogen atoms 

Reduction

Gain of hydrogen atoms 

which molecules are being oxidized, in cellular respiration

Glucose is being oxidized (loss of hydrogen atoms)

which molecules are being reduced in cellular respiration

Oxygen is being reduced (gain of hydrogen atoms)

• The reactants, final products, location, and ATP yield of each of the following phases of cellular respiration:

Glycolysis

Reactants: Glucose, ADP, NAD+

Final product: Pyruvate, ATP, NADH

Location: Cytoplasm 

ATP yield: 2 per glucose (4 total) → spent two ATP to make four ATP (+2 ATP profit)

• The reactants, final products, location, and ATP yield of each of the following phases of cellular respiration:

Pyruvate oxidation

Pyruvate oxidation

Reactants: Pyruvate, NAD+, Coenzyme A (CoA)

Final product: CO2, Acetyl Coenzyme A, NADH, 

Location: Mitochondria 

ATP yield: 0

• The reactants, final products, location, and ATP yield of each of the following phases of cellular respiration:

Citric acid cycle

Reactants: Acetyl CoA, NAD+, ADP, FAD

Final product: CoA, CO2, NADH, ATP, FADH2

Location: Mitochondria 

ATP yield: 2 

• The reactants, final products, location, and ATP yield of each of the following phases of cellular respiration:

Oxidative phosphorylation

Reactants: NADH, FADH2, ½ O2, ADP

Final product: NAD+, FAD, H2O, ATP

Location: Mitochondria 

ATP yield: 28

• The investment and production of ATP during the two halves of glycolysis

2 ATP’s are initially spent during the first half of glycolysis (investment phase), but 4 ATP’s are then made in the second half (payoff phase) for a net profit of 2 ATP per glucose

Be able to keep track of the carbon atoms at each stage from glucose to carbon dioxide

Glucose-

(C₆H₁₂O₆, 6 carbons):

The starting molecule

• Be able to keep track of the carbon atoms at each stage from glucose to carbon dioxide

Glycolysis → 2 Pyruvates (C₃ each)

Glucose (6C) splits into 2 molecules of pyruvate, each 3 carbons

No carbons are lost yet; all 6 carbons are still present in 2 pyruvates

Be able to keep track of the carbon atoms at each stage from glucose to carbon dioxide

Pyruvate → Acetyl CoA (C₂):

Each pyruvate (3C) loses 1 carbon as CO₂ → forms Acetyl CoA (2C)

Now 2 carbons per pyruvate enter the Citric Acid Cycle

2 CO₂ are released per glucose at this step

• Be able to keep track of the carbon atoms at each stage from glucose to carbon dioxide

Citric Acid Cycle

Each Acetyl CoA (2C) combines with oxaloacetate (4C) to form citric acid (6C)

During the cycle, the 2 carbons from Acetyl CoA are oxidized and released as CO₂

For 1 glucose (2 Acetyl CoA) → total of 4 CO₂ released in the Citric Acid Cycle

• Be able to keep track of the carbon atoms at each stage from glucose to carbon dioxide

Total CO₂ Produced:

2 CO₂ from pyruvate → Acetyl CoA

4 CO₂ from Citric Acid Cycle

Total = 6 CO₂ per glucose

• The phases in which NADH and FADH2 are produced, and the phase in which they are used

Citric acid cycle produces NADH and FADH2 and Oxidative Phosphorylation phase uses NADH and FADH2

• The process of utilizing an electron transport chain to generate a concentration gradient of H+ ions

Active transport is moving a substance from an area of Low Concentration to an area of High Concentration (“against” or “up” the concentration gradient); Carried out by pump proteins

• The connections of cellular respiration to the pathways involving other key organic molecules, such as fats, amino acids, and carbohydrates

All three carbohydrates, fats, and proteins are connected through cellular respiration because they break down products and feed into the same energy producing pathways.

Oxidation

Hydrolysis Exergonic; The loss of energy, electrons, or hydrogen

Reduction

Dehydration Endergonic; The gain of energy, electrons, or hydrogen

Glucose

Glucose is a simple sugar (a monosaccharide) that serves as the main source of energy for most living organisms

Glyceraldehyde 3-Phosphate

Formed during glycolysis, helps convert glucose into pyruvate during glycolysis, releasing energy for the cell

Pyruvate

Produced at the end of glycolysis from glucose and is converted into acetyl-CoA, releasing CO2

Acetyl-CoA

Formed from pyruvate before the citric acid cycle, it carries the carbon atoms from glucose to the citric acid cycle for further energy extraction

NAD+

An electron carrier molecule that accepts electrons and hydrogen during oxidation reactions, ​​when NAD+ gains electrons and a hydrogen, it becomes NADH

NADH

Carries high energy electrons to the electron transport chain, where it helps produce ATP

FAD

Another electron carrier similar to NAD+, when it gains electrons and hydrogen, it becomes FADH2

FADH2

Also donates electrons to the electron transport chain, producing slightly less ATP than NADH