Protein Notes

PROTEINS

What are the characteristics

and functions of proteins?
What are enzymes and why

are the beneficial to
chemical reactions?

Multiple Choice

Which macromolecule is composed of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus 

• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

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Any guesses on

what these

proteins are or
their functions?

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Proteins

● The monomer of proteins is called an amino acid.
● Amino acids have a general structure as pictured

below:

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Multiple Choice

When these bond together, they form a protein

• Amino Acids

• Peptide Bonds

• Ribose

• Nucleotides

Multiple Select

Which elements can be found in proteins?

• C

• H

• N

• P

• O

Proteins

● There are 20 different

amino acids.

● Your body can make 12

amino acids, but you
must get the other 8
from your diet.

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Making a Protein

● The presence of the

amino and carboxyl
groups on each
amino acid makes
covalent bonding
easy.

Making a Protein

● The presence of the

amino and carboxyl
groups on each
amino acid makes
covalent bonding
easy.

Making a Protein

● Protein shape is created by linking together

various amino acids to create a polypeptide chain.

● The bonds holding this chain of amino acids

together are called peptide bonds.

● The polypeptide will fold into a 3D shape, which is

when a functional protein is created. Until the
protein is folded, it has no function.

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Let’s draw this in
your notes!

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Function of Proteins

1. Structure proteins are

used for support.

Ex: Connective tissue like
tendons and ligaments
and keratin that forms
your hair and fingernails.

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Function of Proteins

2. Transport proteins

move substances
throughout the body.

Ex: Hemoglobin transports
oxygen from the lungs to
cells for cellular
respiration.

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Function of Proteins

3. Hormone proteins

coordinate various
body activities.

Ex: Insulin regulates the
amount of sugar in the
blood.

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Function of Proteins

4. Contractile proteins

help control
movements.

Ex: Muscles containing
actin and myosin contract
and allow for controlled
movement of the body.

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Function of Proteins

5. Enzymatic proteins

speed up the rate of a
chemical reaction.

Ex: Amylase found in
saliva breaks down starch
into sugars.

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Function of Proteins

6. Immune System proteins

help the body defend
against invaders.

Ex: Antibodies act like flags
that stick to invaders and
mark them for destruction
by the white blood cells.

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Multiple Choice

Proteins are polymers of __________.

• amino acids

• fatty acids

• carboxylic acids

• nucleic acids

Multiple Choice

All proteins

• have a unique structure that determines their unique function.

• are exactly the same in function but different in structure.

• are exactly the same in structure but different in function.

• are enzymes.

Multiple Choice

The order of amino acids determines the ______ and ultimately the function of a protein.

• shape

• color

• flavor

• texture

Multiple Choice

What is a peptide bond?

• Bond that holds two amino acids together.
• A bond that holds hydrogen and oxygen molecules together.
• A bond that holds the phosphate group of one nucleotide and a sugar of a neighboring nucleotide.
• A bond that is formed by the sharing of electrons.

Multiple Choice

Protein is found in the following food:

• Meat, poultry, and fish

• Pasta

• Leafy Greens

• Any of the above

Multiple Choice

What is the shape of a protein?

• chains

• folded chains

• rings

• honeycomb

Multiple Choice

Which describes the functions of proteins in living things?

• structural, transport, signaling, catalysts, etc.

• stores and transmits genetic information

• stores energy and makes up cell membranes

• quick energy and forming cell structure

Denaturing of Proteins

● If there is a change in temperature, pH, or salinity,

(homeostasis) a protein may lose its shape, return
to its polypeptide form, and lose its function.

● This is called denaturation.

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Food Examples of Proteins:

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Proteins Facts

● Proteins provide 4 kCal/g of

energy, just like carbohydrates.

● These will not be used as energy

if carbs and/or lipids are present.
These are a last resort energy
source.

● Most proteins end in -in.

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Cellular Examples of Proteins:

91

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Multiple Choice

Which macromolecule(s) have the elements Carbon, Hydrogen, and Oxygen? 

• Proteins & Nucleic Acids
• Carbohydrates & Lipids
• Lipids & Proteins
• Carbohydrates & Nucleic Acids

​Concept 5: Enzymes

Catalysts

● Catalysts are substances

that change the rate of a
chemical reaction or allow a
chemical reaction to occur at
a lower than normal
temperature.

● Each catalyst works best at a

specific temperature and pH.

Catalysts

● Catalysts work by lowering

the activation energy of a
chemical reaction to
increase the reaction rate.

● It is not consumed or

altered during the reaction,
so it can be used over and
over again.

Enzymes

● Enzymes are proteins that serve

as catalysts in living organisms.

● They are involved in many of the

chemical reactions necessary for
organisms to live, reproduce, and
grow.

● Ex: digestion, respiration,

reproduction, movement, cell
regulation, etc.

Enzymes

● Enzymes are able to

lower the activation
energy needed for a
reaction to occur,
which often speeds
up the reaction.

● They are known as

biological catalysts.

Enzymes

● Ex: Carbonic Anhydrase

speeds up the reaction
of removing CO2 from
the body

● Without this enzyme,

the reaction would
happen too slowly.

Enzymes

● Enzymes are very specific

and can catalyze only one
chemical reaction by working
on one particular reactant
called a substrate.

● The structure of enzymes can

be altered by temperature
and pH when they are
denatured.

Enzymes

● Enzymes work by binding with

the proper substrate at the
active site.

● When they are attached, it is

called the enzyme-substrate
complex.

● After the reaction has occurred,

the product(s) isreleasedand
the enzyme is left unchanged.

Multiple Choice

Extra Credit Challenge: Picture this - you're a tiny scientist, small enough to observe the enzymatic hydrolysis of sucrose by the enzyme sucrase up close and personal. You see glucose and fructose forming right before your eyes! Now, you know that the activity of an enzyme is influenced by factors like temperature and pH, and each enzyme has its own sweet spot where it works best. For sucrase, that's a pH range of 4 - 8. But oh no! The pH of your tiny lab has suddenly dropped to 2. What do you think will happen to point D in your model?

• Nothing will change at point D because of the drop in pH. Only temperature has the power to denature the enzyme.

• More of the substrate (A) will cozy up into the active site (C), leading to a party of products.

• The enzyme (B) will become a bit more selective, allowing less of the substrate (A) to enter the active site (C).

• The substrate (A) will find itself locked out of the active site (C) because the enzyme has decided to change its shape.

Multiple Choice

Pop Quiz! Take a look at this graph, it's showing the activity levels of three well-known digestive enzymes. The scale is from 0 (no activity) to 12 (highest activity). Can you tell me which enzyme is having a party at a neutral pH of 7?

• Is it Amylase and pepsin?

• Or just Amylase?

• Maybe it's Pepsin?

• Or could it be Trypsin?

Multiple Choice

Imagine you're a tiny explorer, journeying through the human body. You come across the pancreas, a bustling organ that's busy helping with digestion. It's secreting trypsin, a powerful enzyme that's breaking down proteins. Now, think about what happens to our hero, the trypsin, after it's done digesting a protein. What do you think happens?

• Our hero, the trypsin, isn't changed by the reaction and gets ready for the next adventure.

• After its heroic act, the trypsin is destroyed and a new hero must take its place.

• After its mission, trypsin transforms into a lipid and becomes a storage unit for energy.

Multiple Choice

Imagine you're a tiny explorer, journeying through the human body. You come across the pancreas, a bustling organ that's busy helping with digestion. It's secreting trypsin, a powerful enzyme that's breaking down proteins. Now, think about what happens to our hero, the trypsin, after it's done digesting a protein. What do you think happens?

• Our hero, the trypsin, isn't changed by the reaction and gets ready for the next adventure.

• After its heroic act, the trypsin is destroyed and a new hero must take its place.

• After its mission, trypsin transforms into a lipid and becomes a storage unit for energy.

Multiple Choice

Imagine you're a tiny detective, investigating the world of macromolecules. You come across insulin, hemoglobin, and enzymes. Which macromolecule group do you think they belong to?

• Carbohydrates

• Lipids

• Nucleic acids

• Proteins

Multiple Choice

Imagine this! You're at a picnic, munching on a juicy hamburger. As you take a bite, your body kicks into action. An enzyme called salivary lipase jumps in, starting the fat digestion process. Now, can you tell me, what's the BEST way to describe the role of these super enzymes in digestion?

• Are enzymes like acids that physically break down food molecules?

• Or are enzymes cells that secrete saliva and other necessary substances needed for digestion?

• Could enzymes be proteins that speed up the process of chemically breaking down food molecules?

• Or do enzymes moisten food to help teeth in the mechanical process of grinding and chewing?

Enzyme Structure and Reaction

Enzymes

● Enzyme structure consists of the

active site, which is where the
substrate will bind with the
enzyme and where the reaction
occurs.

● Enzymes have a complementary

shape to their substrate.

● This is referred to as the lock and

key model.

Enzymes

● Enzymes can be used in anabolic reactions to bind two

substrates together and create a product.
○ Ex: creating lactose from galactose glucose

Enzymes

● Enzymes can also be used in catabolic reactions to break

a substrate into two products.
○ Ex: breaking down sucrose (table sugar) into glucose

and fructose

Enzymes

● Enzymes are often named by the

reactionthat it is involved in.

● Ex: Lactase breaks down lactose

into galactose and glucose.

● Enzyme names always end in

-ase.

● Ex: Amylase, DNA polymerase,

Lipase, etc.

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