3. Complete the sentences:

1. Biochemistry focuses on…

2. Biochemistry analyzes…

3. The earliest work in biochemistry dealt with…

4. The first living things arose from…

5. The modern study of biochemistry centers around…

6. Some biomolecules are…

7. No one has yet created living cells….

4. Find and write out a summarizing (key) sentence for each paragraph.

5. Watch “Introduction to Biochemistry” and do the following tasks:

1. Answer the questions:

1. What does biochemistry study?

2. How many types of biomolecules are there?

3. Why is it important to know the properties of water in biochemistry?

4. What is metabolism?

5. Why is it important to understand living systems at the molecular level?

6. What aspects are involved in every biochemical study?

7. Why is biochemistry important?

1. Decide if the statements are true or false:

1. There is no evidence of the relationship of the structure of the biomolecule and its function.

2. The fundamentals of biochemistry have been uncovered in the recent 20 years.

3. Biochemistry studies the life and living organisms, including their structure, function, growth, evolution, distribution, identification and taxonomy.

4. It is very important to use the terminology of biochemistry in a consistent way.

5. Biochemistry is fundamentally a physical science.

6. Prepare short talks (1 minute) on the following topics:

1. What is biochemistry?

2. What do biochemists do?

3. Why is biochemistry important?

Part II

1. Match the words with their definitions.

Diverse	dʌɪˈvəːs	the process of taking food into the body through the mouth (as by eating)
Enzyme	ˈɛnzaɪm	a simple sugar, such as glucose or  fructose,  that does not hydrolyse  to yield other sugars
Consumption	kənˈsʌmpʃən	Any of a large number of  compounds that are found in living cells, contain carbon, oxygen,  hydrogen, and nitrogen,and join  together to  form proteins.
amino acid	|əˈmiːnəʊ|  |ˈæsɪd|	not like another in nature, quality, amount, or form
Monosaccharide	ˌmɒnəʊˈsækəˌraɪd; -rɪd	any of a group of complex proteins or  conjugated proteins that are produced by  living cells and act as catalysts in specific biochemical  reactions
Cellulose	ˈsɛljʊˌləʊz; -ˌləʊs	any of a class of aliphatic  carboxylic acids,  such as palmitic acid, stearic acid, and oleic  acid,  that form part of a lipid molecule
fatty acid	ˈfætiˈæsɪd	vitally important; absolutely  necessary
essential	ɪˈsɛnʃəl	a polysaccharide consisting of long  unbranched chains of linked  glucose units:  the main  constituent of plant cell walls and used in making paper,  crayon, and film

Proteins

Many biochemists consider proteins the most important substances for study because they perform amazingly diverse tasks. For example, enzymes, the subject of so much early research, are proteins. Living things depend on enzymes to catalyze, or stimulate, important reactions that would not occur in their absence. Other proteins transport important materials around the cell or body, or store these materials for later consumption. Antibodies are specialized proteins produced by the immune system in response to a specific pathogen. They bind to disease-causing agents within the body, allowing immune system cells to recognize and destroy harmful intruders. Proteins perform many other functions within the body.

Most proteins are large, intricate molecules with chain-like structures that fold into a specific shape. Individual sections of the chain are made up of component amino acids. Though there are many kinds of amino acids, only 20 are used by all living things to produce thousands of different proteins. Biochemists have created several new amino acids that do not occur in any living organisms and have found important uses for them in industrial products.

Carbohydrates

Carbohydrates, the largest group of biomolecules, are dietary fuel—this is one of their major uses in living organisms. The most basic carbohydrates are monosaccharides, small simple sugar molecules. The most important of these is glucose, the body's major source of metabolic energy. More complex carbohydrates are used for longer-term storage of energy within the body, particularly in plants. These polysaccharides are also known as starches.

Very large carbohydrate molecules are usually not digested by humans, but still serve important tasks in many organisms. Cellulose gives structure to plants; it is the major component of wood and paper. Chitin, a glucose-based polymer, forms the exoskeleton in insects. Glycoproteins, or carbohydrates attached to amino acids, have important functions in the immune system and for blood clotting.

Lipids

Lipids are an important, although difficult to define, group of biochemicals. They are most commonly categorized as fats, but lipids include fats, oils, waxes, certain vitamins, some hormones, components of some cell membranes, steroids, fatty acids, and other related biomolecules. Until 1979 only two functions of lipids were known: energy storage and components of cell membranes. Then the lipid now known as platelet-activating factor was shown to help activate or mediate many immune responses. Following this discovery, other lipids were found to have important functions in sending signals within and between cells and transporting energy throughout the body.

Fatty acids are a class of lipids that are particularly important to human health. The body can produce most fatty acids, but those that must be consumed in the diet are called “essential fatty acids.” Maintaining the correct balance between omega-3 and omega-6 fatty acids may help reduce the risk of cardiovascular disease such as high cholesterol, high blood pressure, heart attack, and stroke. Other studies have suggested that fatty acids might have a positive influence on many diseases such as diabetes, arthritis, and several types of cancer.

Nucleic acids are biopolymers, or large biomolecules, essential to all known forms of life. They are composed of monomers, which are nucleotides made of three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base. If the sugar is a simple ribose, the polymer is RNA (ribonucleic acid); if the sugar is derived from ribose as deoxyribose, the polymer is DNA (deoxyribonucleic acid).

Nucleic acids are arguably the most important of all biomolecules. They are found in abundance in all living things, where they function to create and encode and then store information in the nucleus of every living cell of every life-form organism on Earth. Nucleic acids are the main information-carrying molecules of the cell, and, by directing the process of protein synthesis, they determine the inherited characteristics of every living thing. In turn, they function to transmit and express that information inside and outside the cell nucleus—to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information is contained and conveyed via the nucleic acid sequence, which provides the 'ladder-step' ordering of nucleotides within the molecules of RNA and DNA. Strings of nucleotides are bonded to form helical backbones—typically, one for RNA, two for DNA—and assembled into chains of base-pairs selected from the five primary, or canonical, nucleobases, which are: adenine, cytosine, guanine, thymine, and uracil; note, thymine occurs only in DNA and uracil only in RNA. Using amino acids and the process known as protein synthesis,^[3] the specific sequencing in DNA of these nucleobase-pairs enables storing and transmitting coded instructions as genes. In RNA, base-pair sequencing provides for manufacturing new proteins that determine the frames and parts and most chemical processes of all life forms.