digestive system + enzymes + organic molecules

Nutrients

Chemical building blocks our bodies need to live, grow, and repair themselves, also providing energy.

Energy

The ability to do work, powering activities and helping build complex muscles.

Macronutrients

Chemical building blocks provided by food in large quantities, including carbohydrates, proteins, and fats.

Carbohydrates

Macronutrients broken down into simple sugars, used to build cell-surface markers and energy-storage molecules.

Proteins

Macronutrients broken down into amino acids, used to assemble new proteins with many different functions in the body.

Fats

Macronutrients broken down into fatty acids and glycerol, used to build molecules that form cell membranes.

Nucleic Acids

Components provided in smaller amounts (not macronutrients), broken down into individual nucleotides, used to build DNA and RNA.

Essential Nutrients

Nutrients that cells cannot synthesize and must be obtained through diet.

Essential Amino Acids

Nine specific amino acids out of 20 that cannot be synthesized by the body and must be obtained through diet.

Digestion

The process of breaking down huge food molecules into smaller pieces through a series of chemical reactions, starting in the mouth.

Enzyme

A protein that catalyzes (speeds up) a chemical reaction.

Substrate

A molecule to which an enzyme binds and on which it acts.

Active Site

The specific part of an enzyme that binds to the substrate.

Catabolic Reactions

Metabolic reactions that break down larger structures into smaller ones (bond breaking).

Anabolic Reactions

Metabolic reactions that build new structures from smaller subunits (bond building).

Activation Energy

The energy required for a chemical reaction to proceed.

Catalysis

The process of facilitating a chemical reaction without the catalyst itself being used up in the reaction.

Denatured Protein

A protein whose shape and function have been disrupted, often by extreme environmental conditions like heat or pH.

Micronutrients

Nutrients required by organisms in smaller amounts than macronutrients, including vitamins and minerals, important for maintaining health and playing structural and functional roles.

Minerals

Inorganic elements required by organisms for normal growth, reproduction, and tissue maintenance (e.g., calcium, iron, potassium, zinc).

Vitamins

Organic molecules required in small amounts for normal growth, reproduction, and tissue maintenance.

Coenzymes

Small organic molecules (often vitamins) required to activate enzymes.

Cofactors

Inorganic micronutrients (often minerals like zinc, copper, iron) required to activate an enzyme.

organic molecules

molecules that contain carbon and hydrogen

Why does carbon bond with four other elements?

It is to gain four more electrons since Carbon only has four electrons in its outer shell. Carbon normally shares electrons with Carbon, Hydrogen, Oxygen and Nitrogen.

Hydrocarbons

Chains composed of carbon and hydrogen

Functional Groups (R-groups)

molecules that are attached to hydrocarbons that gives them their properties.

Monomer

small chemical unit that makes up a polymer

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Dehydration Synthesis

WATER is REMOVED from the chemical reaction, which then allows monomers to bond

Hydrolysis

WATER is ADDED to break bonds.

Polymers => Monomers

monosaccharides

single molecule (simple sugar)

ex. glucose

Disaccharides

two monosaccharides bonded together

ex. Maltose (glucose + glucose)

Polysaccharides

large molecules formed by multiple monosaccharides. Energy storage molecules

Starch = glucose storage for plants

Glycogen = glucose storage for animals

Structural: cellulose for plant walls and chitin for lobsters

Lipids

long chains of carbon and hydrogen

used for: cell membrane, waterproof skin, hair, feathers. Also used for long-term energy storage

ex: steroids, fats, phospholipids

Saturated Fats

SOLID at room temperature. It does not have double bonds.

ex: Butter

Unsaturated Fats

LIQUID at room temperature. Has double bonds.

ex: oil

Triglycerides

composed of 1 glycerol and 3 fatty acids.

storage for extra calories

Phospholipids

a lipid consisting of a glycerol bound to two fatty acids and a phosphate group.

Present in the cell membrane: Polar head and non-polar tail

Sterols

lipids with four fused ring carbon skeletons

Cholesterol

Sterol common in cell membranes, also in many hormones.

Amino acids

organic molecules with carboxyl and amino groups

r group determines its properties

It is a monomer

Polypeptides

long chains of amino acids

it is a polymer

Four levels of protein structure

primary, secondary, tertiary, quaternary

primary structure

sequence of amino acids

secondary structure

Either an alpha helix (coils) or beta pleated sheet (folds) in polypeptide chain. (via H-bonds)

tertiary structure

interactions of the R groups of the amino acids making up the chain.

quaternary structure

Results from two or more polypeptide subunits.

nucleic acids

Polymers of nucleotide monomers.

DNA and RNA

composed of phosphate, 5-carbon sugar, and nitrogen base

DNA

Deoxyribonucleic Acids

Sugar: Deoxyribose

Double Helix

stores genetic information

(Bases: Guanine, Adenine, Thymine and Cytosine)

RNA

ribonucleic acid

Sugar: Ribose

Single-stranded

helps to make protein

(Bases: Guanine, Adenine, Uracil and Cytosine)

stomach

An organ of the digestive system where mechanical and chemical breaking down of food happens

Mucus lning produces gastric juices, HCl (hydrochloric acid), and pepsin

esophagus

A muscular tube that connects the mouth to the stomach

Performs peristalsis to pump the food through the tube

large intestine

Absorbs water and forms feces (hardens it)

Removes toxins

Makes short-chain fatty acids

E.Coli live in here to feed on undigested lactose

Trachea

Windpipe

Helps prevents choking

Bile duct

Transports bile from the liver and gall bladder to the small intestine

salivary glands

Makes saliva

Lysozymes break down chemical bonds

Saliva breaks down polysaccharides into disaccharides

Starts chemical digestion

Saliva has amylase

Liver

Breaks down and filters toxins

Produces bile

Stores nutrients

mouth

where digestion begins

small intestine/duodenum

Long hollow tube where most absorption of nutrients occurs

Starts the break down of chyme

Uses bile from liver and gall bladder

Uses trypsin (proteins), lipase (fats), and amylase (carbs) from pancreas

pancreas

Produces amylase to break down carbs in the small intestine

Produces trypsin to break down proteins in the small intestine

Produces lipase to break down fats in the small intestine

Sodium bicarbonate has a high pH, neutralizing the chyme

gall bladder

Stores and concentrates bile from the liver and brings it to the bile duct

rectum

stores solid waste and compresses into more solid form

Has 2 sphincters, one where the poop is brought to anus, other is the elimination of poop

Feces made of cellulose and bacteria

chemical digestion

breaking down food with enzymes

mechanical digestion

physically crushing, mashing or breaking down food into smaller pieces

chyme

thick slippery paste of food molecules formed from the broken down pieces of food in the stomach

hydrochloric acid

kills bacteria in stomach and gives an acidic environment for enzymes to work

villi

fingerlike projections in the small intestine that increase surface area

peristalsis

the process of food being pumped through the esophagus

epiglottis

flap of tissue that covers the trachea when swallowing food

Makes sure food and liquids go to the esophagus not the respiratory system

bacteria

organisms found in the large intestine that help with digestion of solid matter

oral cavity

Mechanical and chemical digestion

Uses teeth and enzymes in saliva to break down starches and fats

Substrate is amylose (carbs)

tongue

Helps with mechanical digestion

Moves food around for chewing and swallowing

teeth

Anchored in the jaw

Does most of the mechanical breakdown

soft palate

Blocks food and liquids from entering the nasal tube when swallowing

Prevents choking

Pharynx/Throat

Tube that connects the mouth or trachea to the esophagus

Pyloric sphincter

Controls the passage of chyme from the stomach to the small intestine

pepsinogen

pre enzyme of pepsin

pepsin

enzyme that helps digest proteins turns proteins into long-chain polypeptides

trypsinogen

pre enzyme to trypsin

trypsin

enzyme used to digest proteins. turns long-chain polypeptides into short-chain polypeptides

Cardiac/Esophageal Sphincter

Prevents chyme in the stomach from going back up the esophagus

Controls what goes from the esophagus into the stomach

cecum

Absorbs fluids and electrolytes

Mixes remaining waste with mucus to lubricate it

appendix

Regulates the movement through the digestive tract

Produces mucus

Stores and releases bacteria when stressed/ill

Jejunum

Absorbs carbs, proteins, fats, and vitamins from chyme

Has muscular contractions

Where the most absorption happens in the digestive system

ileum/ileocecal sphincter

Completes absorption of carbs, proteins, fats, water, and vitamins from chyme

Anus

Responsible for eliminating waste products

Holds feces

Has a mucus membrane

Prevents bacteria and pathogens from entering the body