Biochemistry

Biochemistry

Table of Contents

Section 1 Carbon Compounds

Section 2 Molecules of Life


Objectives

• Distinguish between organic and inorganic compounds.

• Explain the importance of carbon bonding in biological molecules.

• Identify functional groups in biological molecules.

• Summarize how large carbon molecules are synthesized and broken down.

• Describe how the breaking down of ATP supplies energy to drive chemical reactions.


Carbon Bonding

• Organic compounds contain carbon atoms and are found in living things.

• Most inorganic compounds do not contain carbon atoms.

• Carbon atoms can readily form four covalent bonds with other atoms including other carbon atoms. The carbon bonds allow the carbon atoms to form a wide variety of simple and complex organic compounds.

Carbon Bonding



Functional Groups

• Functional groups are groups of atoms that influence the properties of molecules and the chemical reactions in which the molecules participate.

Large Carbon Molecules

• Condensation reactions join monomers (small simple molecules) to form polymers. A condensation reaction releases water as a by-product.

• In a hydrolysis reaction, water is used to split polymers into monomers.


Energy Currency

• Adenosine triphosphate (ATP) stores and releases energy during cell processes, enabling organisms to function.


Objectives

• Distinguish between monosaccharides, disaccharides,and polysaccharides.

• Explain the relationship between amino acids and protein structure.

• Describe the induced fit model of enzyme action.

• Compare the structure and function of each of the different types of lipids.

• Compare the nucleic acids DNA and RNA.


Carbohydrates

• Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen in a ratio of about one carbon to two hydrogen atoms to one oxygen atom.

• Carbohydrates are a source of energy and are used as structural materials in organisms.

Click below to watch the Visual Concept.

Visual Concept

Carbohydrates



Carbohydrates, continued

• Monosaccharides – Carbohydrates are made up of monomers called

monosaccharides. – One Ring

Ex. Glucose (cell’s primary source of energy)

Simple Sugars


Carbohydrates, continued

• Disaccharides and Polysaccharides– Two monosaccharides join to form a double sugar

called a disaccharide. Ex. Sucrose (Table Sugar)– Two Rings

– A complex sugar, or polysaccharide, is made of three or more monosaccharides. Ex Starch and Cellulose


Visual Concept

Disaccharides


Role of Carbohydrates• In Plants– Carbohydrates: synthesized during the

process of photosynthesis– Plants

• Use them as a source of energy• Store them in the cells.

• In Animals– Carbohydrates: consumed as sugars, starches, and fiber– When complex carbohydrates are consumed, digestion breaks the

bonds between the larger carbohydrate molecules so that individual simple sugars can be absorbed into the bloodstream through the walls of the intestines.

• The bloodstream carries the simple sugars to cells throughout the body where they cross into the cells through the cell membrane.

• Once inside the cells, simple sugars are used as fuel in the process of cellular respiration, releasing energy which is stored as ATP.

– If an organism has a greater supply of carbohydrates than needed for its energy requirements, the extra energy is converted to fats and stored by the body.

Carbohydrates• Functions

– Energy Source• Glucose in cells is the primary source of energy -

fuel for cellular respiration

– Energy Storage (short term)• Glycogen in the liver of animals• Starch in the structures of plants

– Structural Support• Cellulose forms cell walls in plants

– Also an important source of fiber for animals to stimulate the digestive system


Proteins

• Proteins are organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen.

• Proteins have many functions including structural, defensive, and catalytic roles.

• Amino Acids

– Proteins are made up of monomers called amino acids. There are 20 different types of amino acids. The sequence of amino acids determines a protein’s shape and function.

– 12 amino acids are made in the human body

– Humans need to consume the other 8 amino acids from sources such as nuts, beans, or meat.

Role of Proteins• Proteins: more important as a source of building blocks than as a source of energy. can function as an energy source only if there is a shortage of carbohydrates or lipidsBecause of their structures, proteins serve different functions.

– Structural proteins: used for support such as connective tissue and keratin that forms hair and finger nails.

– Transport proteins: transport many substances throughout the body such as hemoglobin which transports oxygen from the lungs to the other parts of the body to be used by cells in cellular respiration.

– Hormone proteins: coordinate body activities such as insulin which regulates the amount of sugar in the blood.

– Contractile proteins: help control movement such as proteins in the muscles which help control contraction.

– Enzymatic proteins: accelerate the speed of chemical reactions such as digestive enzymes which break down food in the digestive tract.


Visual Concept

Amino Acids



Proteins, continued

• Dipeptides and Polypeptides– Two amino acids are joined by peptide bonds to

form a dipeptide.– A long chain of amino acids is called a

polypeptide.

Structure of Proteins



Proteins, continued

• Enzymes– Enzymes speed up chemical reactions and bind

to specific substrates. – The binding of a substrate with an enzyme causes

a change in the enzyme’s shape and reduces the activation energy of the reaction.

Enzyme Activity



Lipids• Lipids are nonpolar molecules that store energy and

are an important part of cell membranes. • Fatty Acids

– Most lipids contain fatty acids, unbranched carbon molecules that have a hydrophilic end and a hydrophobic end.


Visual Concept

Fatty Acids



Lipids, continued• Triglycerides

– Triglycerides consist of three fatty acids and one molecule of glycerol.

• Phospholipids– Phospholipids, which make up cell membranes, consist of

two fatty acids and one glycerol molecule.

• Waxes– A wax is made of one long fatty acid chain joined to one

long alcohol.• Steroids

– A steroid is composed of four fused carbon rings.

Role of Lipids• Fats: important to organisms for energy when carbohydrates are scarce, but when there is no shortage of food, stored fat accumulates.

• When fats are consumed, the molecules are broken down during digestion so that individual glycerol and fatty acid molecules are absorbed into the bloodstream through the walls of the intestines.– The blood stream carries the glycerol and fatty acid molecules to

cells throughout the body where the molecules cross into the cells through the cell membrane.

– Once inside the cell, glycerols and fatty acids are stored for later use or used as fuel for cellular respiration if there are no carbohydrates available

• The process of cellular respiration releases the energy that is held in the chemical bonds of the glycerol and fatty acid molecules.

• Functions– Energy Storage (long-term)

• Animals in colder climates will store more fats to use as insulation as well as energy to keep warm

• Stored fats are also used to cushion vital organs– Cellular Membrane Structure

• A major component of the cell membrane is the phospholipid– Building Vitamins and Hormones

• These help regulate our metabolism

• Sources– Can be found in oils, meats, and nuts

Lipids

steroid

-Cholesterol


Nucleic Acids

• A nucleic acid is a large and complex organic molecule that stores and transports information.

Structure of Nucleic Acids


Visual Concept

Nucleic Acids



Nucleic Acids, continued

• The nucleic acid deoxyribonucleic acid (DNA) contains genetic information for cell activities.

• Ribonucleic acid (RNA) molecules play many key roles in building of proteins and can act as enzymes.

Calorie Comparison

• Energy stored in organic molecules determines the caloric value

• Lipids have the greatest chemical bond energy over carbohydrates and proteins

• This can be seen in their calorie comparisons– Proteins 4 calories per

gram– Lipids 9 calories per gram– Carbohydrates 4 calories per gram

Biochemistry

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Transcript of Biochemistry