Cellular Metabolism and Digestive System

How does fermentation allow glycolysis to continue when oxygen runs out? In other words, production of ethanol by yeast or lactic acid by animals regenerates just enough of what molecule to keep glycolysis going?

NAD+

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of

ATP, CO₂, and ethanol.

important products of pyruvate oxidation

2NADH, 2CO₂, and 2 acetyl CoA

Important products of the Citric Acid Cycle

6NADH, 2ATP, 2FADH₂, 4CO₂

Most important products of Glycolysis

2CO₂, 2NADH, 2 pyruvate

Catabolic Rxn

Exergonic - ΔG (negative)

Anabolic Rxn

Endergonic - ΔG (positive)

The final hydrogen ion and electron receptor in aerobic cellular respiration is

O₂

How does the absence of oxygen stop aerobic cellular respiration?

The electron transport chain backs up and NADH is not oxidized back to NAD+ at the ETC

Important products of Oxidative Phosphorylation

28 ATP, H₂O, NAD+, FAD, H+

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

Electron Transport Chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

Which of the following occurs in the cytosol of a eukaryotic cell?

glycolysis and fermentation

The ATP made during fermentation is generated by

substrate-level phosphorylation

In alcoholic fermentation, NAD+ is regenerated from NADH during

reduction of acetaldehyde to ethanol (ethyl alcohol)

One function of both alcoholic fermentation and lactic acid fermentation is to

oxidize NADH to NAD+.

What is the benefit to the organism of allowing glycolysis to continue even if aerobic respiration cannot?

2 ATP/glucose are still produced

What eventually happens to lactate in when oxygen returns?

It is taken to the liver and converted back to pyruvate.

How does fermentation allow glycolysis to continue when oxygen runs out? In other words, production of ethanol by yeast or lactic acid by animals regenerates just enough of what molecule to keep glycolysis going?

NAD+

Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle?

Acetyl CoA

Which of the following statements best describes the relationship between photosynthesis and cellular respiration?

Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules.

What is the summary equation for (aerobic) cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

Glycolysis begins with glucose and ends up with…

two molecules of pyruvate (3-C molecule)

In the presence of oxygen, pyruvate moves into a mitochondrion and

is oxidized in aerobic respiration to make acetyl CoA which enters the Kreb's Cycle.

The electron transport chain is located in the

inner mitochondrial membrane

Where in the body does most digestion take place?

small intestine

What hormone creates gastric juice? Where is it stored?

Gastrin; the stomach

What's another name for the large intestine?

Colon

How is pepsinogen converted to pepsin?

HCl

In which cells is pepsinogen produced?

Chief Cells

What are all the cells in the stomach?

Chief cells, parietal cells, mucous cells, neuroendocrine cells

What is pepsin used for?

protein digestion

What is the role of the pancreas in digestion?

Produces protease, amylase and lipase enzymes. It releases these into the small intestine

What are three main parts of the small intestine?

duodenum, jejunum, ileum

What do the folds in the small intestine do?

increase surface area for absorption

What is the ball of food from the tongue called?

Boleus

What stops food from going from pharynx to larynx rather than to the esophagus?

Epiglottis

What is in the inner wall of the small intestine?

villi

What does the alkaline solution in pancreatic juices do?

Neutralizes the acidic it's of chyme

What is chyme?

a mixture of partially digested food, water, and gastric juices

What does the liver produce?

bile

What are other names for the digestive tract?

alimentary canal, gastrointestinal tract

What causes heartburn?

Backflow of chyme, which causes pain in the esophagus

What are gastric ulcers?

erosion of the stomach wall made by a bacterium called Heliobacter pylori

What do parietal cells secrete?

Hydrogen and Cholride ions

How does Pepsin help with protein digestion?

Breaks down polypeptide chains into smaller ones, which then get digested further into the stomach.

What is a microbiome?

the microorganisms in a particular environment (including the body or a part of the body).

What are the different ducts of the liver?

Cystic duct, Hepatic Duct, and the Bile duct

What is bile?

produced in the liver, stored in the gallbladder, breaks down fat in the small intestine, fat emulsifier

Different classes of enzymes in pancreatic juices

Glycosidases, nucleases lipases, nucleases

What does Sodium Bicarbonate do?

neutralizes acidic chyme

exocrine glands

Glands that secrete substances outward through a duct

endocrine glands

Glands of the endocrine system that release hormones into the bloodstream

What gland is the pancreas

exocrine and endocrine

islets of langrehans

Groups of cells that function as endocrine glands that secrete insulin or glucagon