Molecular Biology Wk 3 Flashcards
what is molecular biology
field of science concerned with studying the chemical structures and processes of biological phenomena that involve the basic units of life, molecules. The field of molecular biology is focused especially on nucleic acids (e.g., DNA and RNA) and proteins—macromolecules that are essential to life processes—and how these molecules interact and behave within cells.
what are biochemicals
The compounds produced by living organisms - The chemistry of life centers around the chemistry of the carbon atom. The small and large carbon compounds made by cells are called organic molecules. Carbon-containing backbones may be linear, branched, or cyclic.
what are functional groups
groupings of atoms that often behave as a unit and give organic molecules their physical properties, chemical reactivity, and solubility in aqueous solution
hydroxl- carbs
carbonyl- lipids
carboxyl- proteins
amino- proteins
phosphate- DNA and ATP
examples of functional groups
hydroxyl
carbonyl
caboxyl
amino
how are biological molecules classified by function
macromolecules
the building blocks of macromlecules
metabolic intermediates
molecules of miscellaneous function
what are the major characteristics of macromolecules
can be divided into four major categories: proteins, nucleic acids, polysaccharides, and certain lipids.
how are macromolecules produced
polymerisation- constructed by their monomers
dehydrating
water is lost
how are macromolecules diassembled
by hydrolysis of the bonds that join the monomers together. Hydrolysis is the splitting of a bond by water. All of these reactions are catalyzed by specific enzymes.
which macromolecules are localized in cellular structures- nucleus, plasma membrane, ribosomes, mitochondria
chromatin in the nucleus- DNA and protein
plasma membrane- carbs and lipids
ribosome- protein and rna
mitochondrion- DNA and lipid
microtubules- protein
starch grain in chloroplast- carbohydrates
cell wall- carbs
what are the building blocks of macromolecules
Sugars, which are the precursors of polysaccharides;
Amino acids, which are the precursors of proteins;
Nucleotides, which are the precursors of nucleic acids;
Fatty acids, which are incorporated into lipids.
types of amino acids
essential
non essential
semi essential
types of nucleotides
A,U,T,C,G
what are metabolic intermediates
In the cell, each series of chemical reactions is termed a metabolic pathway
The compounds formed along the pathways leading to the end products might have no function per se and are called metabolic intermediates .
what are molecules of miscellaneous function
include such substances as vitamins, which function primarily as materials to proteins; certain steroid or amino acid hormones; molecules involved in energy storage, such as ATP; regulatory molecules such as cyclic AMP; and metabolic waste products such as urea.
what are carbohydrates
include simple sugars (or monosaccharides ) and all
larger molecules constructed of sugar building blocks. Carbohydrates function primarily as stores of chemical energy and as durable building materials for biological construction. Most sugars have the general formula (CH2O)n . The sugars of importance in cellular metabolism have values of n that range from 3 to 7.
what is bernards hypothesis
the balance between glycogen formation and glycogen breakdown in the liver was the prime determinant in maintaining the relatively constant homeostatic level of glucose in the blood
what bonds do sugars join by
can be joined to one another by covalent glycosidic bonds to form larger molecules. Glycosidic bonds form by reaction between carbon atom C1 of one sugar and the hydroxyl group of another sugar, generating a
-C- O- C- linkage between the two sugars.
Sugars may also be linked together to form small chains called oligosaccharides ( oligo = few). Most often such chains are found covalently attached to lipids and proteins, converting them into glycolipids and glycoproteins, respectively. Oligosaccharides are particularly important on the glycolipids and glycoproteins of the plasma membrane, where they project from the cell surface.
name some disaccharides
Sucrose and lactose are two of the most common disaccharides. Sucrose is composed of glucose and fructose joined by an α (1 → 2) linkage, whereas lactose is composed of glucose and
galactose joined by a β (1 → 4) linkage.
what are the common properties of lipids
ability to dissolve in organic solvents, such as chloroform or benzene;
lipids of importance in cellular function
Fats
what do fats consist of
Glycerol molecule Three fatty acids
The composite molecule is termed a triacylglycerol (FIGURE ), also known as a triglyceride.
what is the function of fats
Carbohydrates function primarily as a shortterm, rapidly available energy source, whereas fat reserves store energy on a long-term basis.
where are fats stored
Fats are extremely insoluble in water /lack polar groups/ and are stored in cells in the form of dry lipid droplets. Fats are stored in special cells ( adipocytes ) whose cytoplasm is filled with one or a few large lipid droplets. Adipocytes exhibit a remarkable ability to change their volume to accommodate varying quantities of fat
what are steroids
Steroids are built around a characteristic four-ringed hydrocarbon skeleton.
Cholesterol - a component of animal cell membranes and a precursor for the synthesis of a number of steroid hormones, such as testosterone, progesterone and estrogen.
