BIOCHEMISTRY
“The chemistry of life"
At its most basic, biochemistry is the study of the chemical processes occurring in living matter.
It deals with the study of the structures and properties of molecules in living organisms and how those molecules are made, changed, and broken down. By controlling information flow through biochemical signaling and the flow of chemical energy through metabolism, biochemical processes give rise to the complexity of life.
Biochemistry
is the process in which matter from outside an organism is transformed into energy or material for the organism.
is the set of life-sustaining chemical transformations within the cells of living organisms which allow it to grow and reproduce, maintain their structures, and respond to their environments.
Metabolism
Metabolism is usually divided into two categories.
1. Catabolism
- Catabolic Reactions
2. Anabolism
- Anabolic Reactions
that breaks down organic matter and harvests energy by way of cellular respiration (breakdown of substances).
1. Catabolism
break the bonds of complex molecules. In the body, these reactions may be linked to enzyme catalysts allowing for storage of the released energy in the form of ATP (adenosine triphosphate). Polymers yields energy when they are converted to intermediates
Catabolic Reactions
that uses energy to construct components of cells (building up of substances)
2. Anabolism
synthesize complex molecules from simpler molecules using ATP as an energy source. Simple molecules become polymers.
Anabolic Reactions
Energy-carrying molecule found in the cells of all living things. ATP captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes.
ATP (adenosine triphosphate)
WHAT DOES ATP MEAN?
adenosine triphosphate
An ATP molecule is composed of a _____________attached to the ______________. ______________ are attached to the pentose sugar. The phosphate groups are linked to one another by chemical bonds called ____________. The energy of ATP is locked in these bonds.
1. purine base (adenine)
2. pentose sugar (ribose)
3. Three phosphate groups
4. phosphate bonds
The energy in ATP can be released as heat or can be used in the cell as a power source to drive various types of chemical and mechanical activities. For example, when the terminal phosphate group of the ATP molecule is removed by hydrolysis (a decomposition process that occurs when a substance reacts with water), energy is released and ______________ and ________________are formed.
1. adenosine diphosphate (ADP)
2. inorganic phosphate (Pi)
The hydrolysis of ATP is accelerated by an enzyme called ____________________.
The reaction can be written as:
ATP ------?-----> ADP + Pi + energy
adenosine triphosphatase, or ATP-ase
Most of the structures that make up animals, plants and microbes are made from three basic classes of substances: __________________.
1. proteins
2. carbohydrates
3. lipids (often called fats).
As these molecules are vital for life, metabolic reactions either focus on making these molecules during the construction of cells and tissues, or by breaking them down and using them as a source of energy, by their digestion. These biochemicals can be joined together to make_________.
polymers
_________are made up of small repeating basic unit or building blocks known as monomers
Polymers
Polymers are made up of small repeating basic unit or building blocks known as ______
monomers
Macromolecule------Monomer (basic unit)------Polymer
1. Carbohydrates----Monosaccharide ------Polysaccharide (e.g. starch, glycogen, cellulose)
2. Protein-----Amino acid------Polypeptide (e.g. fibrous protein, globular protein)
3. Lipids (fats)-----Glycerol, fatty acid------Triglycerides
- are made of amino acids arranged in a linear chain joined together by peptide bonds.
- Many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, a system of scaffolding that maintains the cell shape.
- are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle.
- Amino acids also contribute to cellular energy metabolism by providing a carbon source for entry into the citric acid cycle (tricarboxylic acid cycle), especially when a primary source of energy, such as glucose, is scarce, or when cells undergo metabolic stress.
Proteins
Proteins are made of _____________ arranged in a linear chain joined together by peptide bonds.
amino acids
Proteins are made of amino acids arranged in a linear chain joined together by _________.
peptide bonds
- are the most diverse group of biochemicals.
Lipids
The fats are a large group of compounds that contain ___________; a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this basic structure exist, including alternate backbones such as sphingosine in the sphingolipids, and hydrophilic groups such as phosphate as in phospholipids. Steroids such as cholesterol are another major class of lipids.
fatty acids and glycerol
- are aldehydes or ketones, with many hydroxyl groups attached, that can exist as straight chains or rings. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals). The basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose. Monosaccharides can be linked together to form polysaccharides in almost limitless ways.
Carbohydrates
Carbohydrates are _____________--, with many hydroxyl groups attached, that can exist as straight chains or rings. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals). The basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose. Monosaccharides can be linked together to form polysaccharides in almost limitless ways.
aldehydes or ketones
It is a measure of energy in food, specifically the measure of heat needed to raise a kilogram or a gram of water by one degree Celsius.
In nutrition, calorie equals one scientific kilocalorie (Kcal).
Calorie (C)
Energy source/Energy utilized in humans
1. Carbohydrates
2. Proteins
3. Alcohols
4. Fats
1. 4 Kcal/gram
2. 4 Kcal/gram
3. 7 Kcal/gram
4. 9 Kcal/gram
are oxidized to produce energy. Excess calories are stored in the body.
Energy storage
A carbohydrate made in the liver and muscle. It is the first fuel used to power activity.
Glycogen
Is the major energy store in the body. Adipose tissue (fatty tissue) is an efficient way to store energy because fat is twice as energy dense as carbohydrates or protein and has less water associated with it. When excess calories are taken in, only limited amounts of carbohydrates and protein can be stored (unless they are converted to fat which uses energy)
Fat (Triacylglycerol)
Protein is not metabolized as an energy source in healthy, well-nourished people. But there is some turnover due to repair and renewal of tissue. The biologic value of animal proteins is highest compared to plant (which may be missing several essential amino acids
Protein
three energy-requiring processes that occur in the body:
1. Basal Metabolic Rate (BMR)
2. Thermic Effect of Food (formerly termed specific dynamic action, or SDA)
3. Physical Activity.
the energy expended by an individual in a resting, postabsoprtive state is called the basal metabolic rate (BMR). It represents the energy required to carry out the normal body functions, such as respiration, blood flow, and maintenance of neuromuscular integrity. This is about ____ of the energy expenditure of a resting person.
1. Basal Metabolic Rate (BMR)----60%
the production of heat by the body increases above the basal level during the digestion and absorption of food. This effect is called the thermic effect of food or diet-induced thermogenesis. Over a 24-hour period the thermic response to food intake may amount to _____ of the total energy expenditure.
2. Thermic Effect of Food (Specific Dynamic Action, or SDA)-----10%
muscular activity provides the greatest variation in energy expenditure. The amount of energy consumed depends on the duration and intensity of the exercise. The daily expenditure of energy can be determined by carefully recording the type and duration of all activities. In an average person, this represents about ________ of his/her total energy consumption.
3. Physical Activity---- 30-40%