Gen Bio I - Cell Membranes, Photosynthesis, & Cellular Respiration

Which process takes place in the presence of oxygen?

aerobic respiration

What is the first phase of cellular respiration?

glycolysis

What is the second phase of cellular respiration?

prep reaction/link reaction

What is the third phase of cellular respiration?

krebs cycle/citric acid cycle

What is the fourth phase of cellular respiration?

electron transport chain/chemiosmosis

What process takes place without the presence of oxygen?

anaerobic respiration

Where does glycolysis take place?

in the cytoplasm outside the mitochondria

What is the main goal of glycolysis?

breakdown of glucose into pyruvate

How many pyruvate are produced per glucose molecule?

2 pyruvate

What happens to pyruvate if there is no oxygen available?

pyruvate is reduced to lactate or ethyl alcohol and CO2

How much ATP is produced during glycolysis?

2 ATP

How much ATP is produced during fermentation?

none/2 ATP are produced by the glycolysis step

What is the main goal of the prep reaction?

pyruvate is oxidized to acetyl CoA and CO2 is removed

How many times does the prep reaction occur?

twice because glycolysis produces 2 pyruvate

Where does the prep reaction occur?

mitochondrial matrix

where does the krebs cycle take place?

mitochondrial matrix

What is the main goal of the krebs cycle?

acetyl CoA is converted to citric acid and a series of oxidation reactions occur

How many times does the citric acid cycle turn?

twice because 2 acetyl CoA molecules are produced per glucose

How much ATP is produced during the krebs cycle?

2 ATP

How much NADH+ is produced during the krebs cycle?

6 NADH+

How much FADH2 is produced during the krebs cycle?

2 FADH2

What are the inputs of the krebs cycle?

2 acetyl groups, 6 NAD, 2 FAD, 2 ADP + P

What are the outputs of the krebs cycle?

4 CO2, 6 NADH+, 2 FADH2, 2 ATP

How much ATP is produced per NADH+ molecule?

3 ATP

How much ATP is produced per FADH2 molecule?

2 ATP

What is chemiosmosis?

use of a H+ gradient over membranes to create ATP

Where does the electron transport chain occur?

the cristae of the mitochondria

Where does NADH+ drop its electrons on the electron transport chain?

complex I

Where does FADH2 drop its electrons on the electron transport chain?

complex II

Where does NAD go after oxidizing and dropping off its electrons?

it returns to pick up more electrons from glycolysis, the prep reaction, and the krebs cycle

Where does FAD go after oxidizing and dropping off its electrons?

it returns to pick up more electrons from the krebs cycle

How much ATP is produced at the end of cellular respiration?

36-38 ATP

What are the outputs of alcoholic fermentation?

2NAD, 2 ethanol, and 2 CO2

What are the outputs of lactic acid fermentation?

lactic acid (lactate), 2 NAD

What process occurs when there is no oxygen present at the end of glycolysis?

fermentation

What are the bubbles produced during alcoholic fermentation?

CO2 bubbles

What is the main goal of fermentation?

to regenerate NAD for glycolysis

What is the first step of glycolysis?

ATP is used and a phosphate is transferred from ATP to glucose

What occurs after the glucose-6-phosphate is rearranged in glycolysis?

ATP is used and a second phosphate is transferred from ATP to the glucose-6-phosphate

What occurs after the second phosphate molecule is transferred to the glucose-6-phosphate molecule?

the 6 carbon splits into two different 3 carbons

What occurs after the 6-carbon splits into two different 3-carbon molecules in glycolysis?

One 3-carbon is converted to match the other 3-carbon, making 2 PGAL molecules

What happens after both 3-carbons become PGAL 3-carbons in glycolysis?

Oxidation and phosphorylation occurs

What happens after the first oxidation and phosphorylation step occurs in glycolysis?

substrate level phosphorylation occurs and yields ATP

What happens after the first instance of substrate level phosphorylation occurs in glycolysis?

rearrangement and removal of H2O

What occurs after rearrangement and removal of H2O in glycolysis?

Substrate level phosphorylation occurs and yields ATP and two molecules of pyruvate per glucose molecule

What is substrate level phosphorylation?

ann enzyme passes a high energy phosphate to ADP to produce ATP

What are the inputs of glycolysis?

1 glucose molecule, 2 NAD, 2 ATP, 4 ADP + P

What are the outputs of glycolysis?

2 pyruvate molecules, 2 NADH+ molecules, 2 ADP molecules, 4 ATP

What is the first step of the krebs cycle?

an acetyl group carried by CoA combines with oxaloacetate to form citrate

What are the inputs of alcoholic fermentation?

2 pyruvate, 2 NADH

What is an obligate aerobe?

an organism that must use repiration and oxygen

What is a facultative anaerobe?

an organism that can use respiration or fermentation

What is an obligate anaerobe?

an organism that must use anaerobic respiration/fermentation

Why do organisms use fermentation?

Anaerobic cellular respiration occurs when oxygen is being used by organisms faster than it can be taken in, such as when we exercise

What are the light reactions of photosynthesis?

The "light reactions" of photosynthesis take place on the thylakoids within the chloroplast, where sunlight is absorbed to be converted into chemical energy. These reactions are known as the "light reactions" of photosynthesis because they are dependent on the absorption of light energy.

What are the dark reactions of photosynthesis?

The "dark reactions" of photosynthesis take place in the stroma, or fluid-filled space, of the chloroplasts, and are light-independent. Here, the carbon dioxide is made into a carbohydrate, and the ATP and NADPH from the "light reactions" are used to build the carbohydrates into glucose.

How is glucose stored in plants?

an insoluble starch molecule

How is glucose stored in animals?

as glycogen in the liver and muscles

What is the chemical equation for photosynthesis?

6CO2 + 6H2O + light energy ----> C6H12O6 + 6O2

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 -----> 6CO2 + 6H2O + Chemical energy (ATP)

What are the general similarities between photosynthesis and cellular respiration?

Both photosynthesis and cellular respiration are cellular processes that cells use to produce the energy needed in order to complete cellular functions. Both photosynthesis and cellular respiration use electron transport chains, and both processes produce ATP, which is the main energy currency of cells.

Describe two situations in which enzymes would stop working

extremely high temperatures and either extremely high or extremely low pH levels

What are enzymes?

Enzymes, which are often proteins, serve as biological catalysts and speed up metabolic chemical reactions within cells.

How do enzymes work?

Enzymes contain an active site where substrates, or a reactant molecule, bind to the enzyme. This active site has a specific shape that matches a specifically shaped substrate. As the chemical reaction occurs, the substrate that had been bound to the enzyme is converted into one of the products of the chemical reaction and is released from the enzyme. The enzyme is unchanged and can then be used again in another reaction.

What is metabolism?

all of the chemical reactions that take place within our cells

How are enzymes involved in metabolism?

they are used as catalysts and lower the activation energy needed for metabolic chemical reactions.

Why is photosynthesis important for regulating the green house effect?

photosynthesis removes carbon dioxide from the atmosphere, which is the gas that animals and humans release or exhale after cells perform cellular respiration. This use of carbon dioxide by plants, algae, and photosynthetic bacteria helps to slow down the rate of building greenhouse gases which contribute to global warming and reduce the greenhouse effect.

When do C3 plants open their stomata?

during the day in response to sunlight and close their stomata during the nighttime.

What will happen when C3 plants are in high light and temperature conditions?

increased photorespiration occurs where C3 plants partially close their stomata to prevent water loss

What are the advantages of using C3 photosynthesis?

C3 photosynthesis is a simple process that requires less steps than occurs in other plants such as C4 and CAM plants, which results in C3 plants being able to use less energy (ATP)

What types of plants use C3 photosynthesis?

grains, crops such as potatoes, legumes, peanuts, and beans, different types of trees, and other plants such as flowers and grasses

When do C4 plants open their stomata?

during the day in response to sunlight; similar to C3 plants

What are the advantages of C4 photosynthesis?

C4 photosynthesis helps to save water in climates with high light and high temperature conditions.

What types of plants use C4 photosynthesis?

tropical crops such as sugarcane

When do CAM plants open their stomata?

at night when temperatures are cooler and the humidity is higher, and close their stomata during the day when there is higher temperatures and lower humidity

What are the advantages of CAM photosynthesis?

it helps to save water in climates that are dry and have higher temperatures

What types of plants use CAM photosynthesis?

desert plants such as cacti

What kinds of molecules can pass through the cell membrane?

small nonpolar molecules

Why is the cell membrane considered a mosaic?

the presence of many proteins embedded within the membrane

What happens when a solute is evenly distributed within a solution?

random movement continues with no net change

What is osmotic pressure?

pressure that develops due to osmosis; results in H2O being absorbed by the kidneys

What is tonicity?

the strength of a solution

What is a hypotonic solution?

a solution with lower solute concentration than inside a cell and causes the cell to swell

What is a hypertonic solution?

a solution with higher solute concentration than inside a cell and causes the cell to shrivel and shrink

What is cytolysis?

the bursting of a cell

What is turgor pressure?

the swelling of a plant cell; how plants remain erect

What is crenation?

the shrinking of red blood cells

What is plasmolysis?

when plant cells lose water and the central vacuole shinks and pulls away from the cell walls

What is hemolysis?

the bursting or rupture of red blood cells

What is collagen?

fibrous tissue that gives skin form and strength; resists stretching

What is fibronectin?

an adhesive protein that binds to integrin in the plasma membrane

What is elastin?

gives the extracellular matrix resilience

What are laminines?

binds to membrane receptors and permits communication between matrix and cytoplasm; forms highways that direct migration of cells during development

What are proteoglycans?

glycoproteins with long carbohydrate side chains; assists with cell signaling and regulates the passage of molecules

What are adhesion junctions?

mechanically attach adjacent cells; hold cells where tissues stretch; internal cytoplasmic plaques attached to the cytoskeleton are joined by intercellular filaments

What are desmosomes?

internal cytoplasmic plaques that firmly attach to the intermediate filament cytoskeleton

What are tight junctions?

zipper-like fastening; serve as barriers in intestines, kidneys, etc.

What are gap junctions?

allows cells to communicate & allows small molecules and ions to pass; important in heart muscle and smooth muscle

What is the primary cell wall?

contains cellulose fibrils where microfibrils are held together by noncellulose substances

What are pectins?

allow the cell wall to stretch when growing