Proteins AP Biology
Summary
TLDRProteins are complex organic macromolecules built from sequences of 20 different amino acids, each with a unique R group. Amino acids join via dehydration synthesis, forming polypeptide chains. These chains fold into specific 3D shapes through interactions among R groups, resulting in secondary and tertiary structures. Some proteins, like hemoglobin, achieve quaternary structure by combining multiple polypeptides. Protein shape dictates function, allowing them to serve various roles in cells, including structural, communicative, metabolic, and transport functions.
Takeaways
- 𧬠Proteins are organic macromolecules made from sequences of amino acids.
- πΏ Amino acids in proteins contain carbon, hydrogen, oxygen, and nitrogen.
- π¬ There are 20 different amino acids, each with a unique R group.
- π Amino acids have a central carbon atom bonded to a hydrogen atom, a carboxyl group, and an amino group.
- π§ Dehydration synthesis forms covalent bonds between amino acids, resulting in a polypeptide chain.
- 𧩠The primary structure of a protein is its specific sequence of amino acids in a polypeptide chain.
- π Secondary protein structure involves alpha helices and beta sheets formed by hydrogen bonding.
- π Tertiary structure arises from interactions among R groups, leading to the protein's unique 3D shape.
- π Quaternary structure occurs when two or more polypeptides join to form a functional protein.
- βοΈ Proteins perform diverse functions such as cell structure, communication, metabolism, defense, and transport.
Q & A
What are proteins made of?
-Proteins are organic macromolecules built from a sequence of amino acids, which are covalently bonded together.
What elements do amino acids and proteins contain?
-Amino acids and proteins contain the elements carbon, hydrogen, oxygen, and nitrogen.
How many different amino acids are there and what makes each unique?
-There are 20 different amino acids, each made unique by their variable region of atoms called an R group.
What is the general structure of an amino acid?
-An amino acid contains a central carbon atom bonded to a hydrogen atom, a carboxyl group, and an amino group. Additionally, each amino acid has a variable region called an R group.
What reaction joins amino acid monomers, and what does it produce?
-The reaction that joins amino acid monomers is called dehydration synthesis, which involves the loss of water and the formation of a covalent bond, producing a polypeptide.
What is the primary structure of a protein?
-The primary structure of a protein is a linear chain of amino acids covalently bonded together, forming a polypeptide.
What are the secondary structures in proteins, and how are they formed?
-Secondary structures in proteins include alpha helices and beta sheets, which are formed by hydrogen bonding between the backbone of the polypeptide.
What determines the tertiary structure of a protein?
-The tertiary structure of a protein is determined by interactions among the R groups of amino acids, including polar, nonpolar, and ionic interactions.
What is quaternary protein structure?
-Quaternary protein structure occurs when two or more polypeptides join together to form a functional protein.
Why is the shape of a protein important?
-The shape of a protein determines its biological function. Proteins must have specific 3D shapes to perform various functions such as cell structure, communication, metabolism, defense, and transport.
What is an example of a protein with quaternary structure?
-Hemoglobin, a protein found in red blood cells that functions in oxygen transport, is an example of a protein with quaternary structure, made from four polypeptides.
Outlines
π¬ Introduction to Proteins and Amino Acids
Proteins are organic macromolecules composed of amino acids covalently bonded together. Each amino acid contains carbon, hydrogen, oxygen, and nitrogen. Despite the 20 different types of amino acids sharing a general structure, the R group varies for each, giving them unique properties. The reaction joining amino acids, known as dehydration synthesis, forms a polypeptide chain. Polypeptides have directionality, with new amino acids added to the free carboxyl terminus. The sequence of amino acids in a polypeptide determines the primary structure of the protein. Functional proteins have distinct three-dimensional shapes.
𧬠Protein Structures and Their Functions
Secondary protein structure involves the polypeptide folding into alpha helices and beta sheets due to hydrogen bonding. Tertiary structure results from interactions between R groups, determining the protein's unique 3D shape and function. Proteins' shapes are crucial for their diverse roles, such as enzymes, hormones, receptors, and transport channels. Additionally, some proteins have a quaternary structure, where multiple polypeptides join to form a functional protein, like hemoglobin in red blood cells. The specific sequence and interactions of amino acids dictate the final structure and function of proteins.
Mindmap
Keywords
π‘Proteins
π‘Amino Acids
π‘Dehydration Synthesis
π‘Polypeptide
π‘Primary Structure
π‘Secondary Structure
π‘Tertiary Structure
π‘Quaternary Structure
π‘R Group
π‘Hydrophilic and Hydrophobic
π‘Function of Proteins
Highlights
Proteins are organic macromolecules, built from a sequence of amino acids, covalently bonded together.
Amino acids and therefore the proteins they build contain the elements carbon, hydrogen, oxygen, and nitrogen.
There are 20 different amino acids, but they share the same general structure.
Amino acids contain a central carbon atom bonded to a hydrogen atom, a carboxyl group, and an amino group, with a variable region called an R group.
The R group is what makes each of the 20 amino acids unique.
The reaction that joins amino acid monomers occurs between the free carboxyl group of one amino acid and the free amino group of another, forming a covalent bond through dehydration synthesis.
A linear chain of amino acids covalently bonded together is called a polypeptide.
Polypeptides are built with a specific directionality, starting with a free amino terminus and adding new amino acids to the free carboxyl terminus.
The sequence of amino acids in a polypeptide represents the primary structure of a protein.
Secondary protein structure involves the polypeptide spiraling and folding into alpha helices and beta sheets due to hydrogen bonding.
Tertiary structure results from R group interactions, causing the protein to bend, fold, and twist into a unique 3D shape.
R groups can be polar, nonpolar, or ionic, and their interactions determine the unique folding pattern of a protein.
Some proteins have a quaternary level of structure, where two or more polypeptides join together to form the final functional protein.
The tertiary shape of a protein determines its biological function.
Proteins perform a variety of functions, including cell structure, communication, metabolism, defense, and transport.
Transcripts
proteins are organic macromolecules
built from a sequence of amino acids
covalently bonded together
amino acids and therefore the proteins
they build contain the elements carbon
hydrogen oxygen and nitrogen
there are 20 different amino acids but
they share the same general structure
amino acids contain a central carbon
atom bonded to a hydrogen atom a
carboxyl group and an amino group
additionally each amino acid has a
variable region of atoms called an R
Group the R Group is what makes each of
the 20 amino acids unique
here are four different amino acids the
r groups are highlighted in red
let's look at how the structure of amino
acids allows for the building of complex
proteins
the reaction that joins amino acid
monomers occurs between the free
carboxyl group of one amino acid and the
free amino group of another
in the reaction water is lost and a
covalent bond is formed this is called
dehydration synthesis
a linear chain of amino acids covalently
bonded together is called the
polypeptide
polypeptides are built with a specific
directionality
directionality refers to the fact that a
molecule has distinct ends and that
reactions between molecules occur in
distinct positions
the first amino acid of the polypeptide
is indicated by the free aminotterminus
new amino acids are always added to the
free carboxyl terminus
each polypeptide is built from a
specific sequence of amino acids a
polypeptide is referred to as the
primary structure of protein
while primary structure is a linear
chain of amino acids functional proteins
have distinct 3D shapes
let's simplify our model to see how this
polypeptide takes shape
in secondary protein structure the
polypeptide Spirals and folds into
General patterns called Alpha helices
and beta sheets
these folds and twists are the results
of hydrogen bonding between the backbone
of the polypeptide
in tertiary structure the protein
continues to bend fold and twist into a
unique 3D shape
tertiary structure results from R Group
interactions the folding that takes
place depends on the sequence and
properties of the r groups in the
polypeptide
the atoms found in R groups determine
the unique chemical properties of each
amino acid R groups can be polar
nonpolar or ionic
amino acids with ionic and polar R
groups are hydrophilic and readily
interact with the water-based
environment of a cell
nonpolar amino acids are hydrophobic
in tertiary structure not only do R
groups interact with the cell
environment they also interact with each
other
polar R groups are attracted to other
polar R groups and charged R groups but
repel nonpolar groups
are groups with opposite charges attract
but R groups with the same charge do not
our group interactions determine the
unique folding pattern that gives a
protein its 3D shape
let's color code these amino acids by
chemical properties of their R groups to
imagine how they might interact
notice the nonpolar hydrophobic amino
acids found in the interior of the
protein while polar and ionic R groups
are interacting with each other and the
aqueous environment
some proteins have a quaternary level of
structure quaternary structure is when
two or more polypeptides join together
to build the final functional protein
an example of a protein with quaternary
structure is hemoglobin a protein found
in red blood cells that functions in
oxygen transport it is made from four
polypeptides
the tertiary shape of a protein
determines its biological function
proteins are the most diverse organic
molecule functioning in cell structure
communication metabolism defense cell
transport and more
to summarize amino acids are the
building blocks of proteins there are 20
different amino acids each with a unique
R Group amino acids contain the elements
carbon hydrogen oxygen and nitrogen
amino acids can be polar nonpolar or
ionic
dehydration synthesis forms covalent
bonds The Joint amino acids into
polypeptide Chains new amino acids are
always added to the free carboxylent
each polypeptide has a unique sequence
of amino acids and represents the
primary structure of a protein
secondary protein structure involves
Alpha helices and beta sheets due to
General hydrogen bonding
tertiary structure is the result of our
group interactions tertiary structure
determines a unique 3D shape of a
protein
the shape of a protein determines its
function
proteins are incredibly diverse and
perform a variety of functions examples
in cells include enzymes hormones
receptors and transport channels
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