Compounds of Life and The Cell



BSCI 124, Straney

The Cell and its Components

The cell- structural and functional building block of organism

-potentially can function independently

I. Chemical Compounds that make up the cell

-properties determined by polar vs nonpolar nature- due to

predominance of water in body

-all form a polymer- a chain of similar compounds (building blocks)

-molecules made from carbon, oxygen, nitrogen and hydrogen

A) Lipids

-building blocks are fatty acids, differ in chain length and saturation

-polymers: mono-, di- and tri-glycerides (triglyceride is a fat or oil)

-diglycerides form membrane (bilayer)

-function: membranes form partitions in water- separate self from

outside; fat and fatty acids store energy and water

B) Carbohydrates

-building blocks are monosaccharides (single sugar)

-polymers: disaccharides (e.g. sucrose is glucose and fructose),

polysaccharides (e.g. cellulose, starch, glycogen are

glucose polymers)

-function: energy storage and currency, structural components

C) Proteins

-building blocks are amino acids (20 different)

-polymers are 100-1000 amino acids long, specific sequence,

many possibilities (eg 20100 - 201000)

-function: enzymes (catalyze specific chemical reactions to make lipids,

carbohydrates, nucleic acids, proteins, as well as other small molecules) and structural components

D) Nucleic Acids

-building block is nucleotide bases (A, G, C, T, U)

-form polymer hundreds to millions of bases long

-DNA- two strands, complementary sequences (A paired with T,

G paired with C)

-function: storage and processing of information for making proteins

II. Structural Components of the cell

-membranes: lipid outer membrane separates cell from outside;

inside, membranes form compartments (organelles)

-cell wall: made of cellulose, provides structural strength

-cytoplasm: watery material inside cell

-filaments: microtubules and microfilament allow movement of cell

and within the cell

-organelles:

-nucleus: stores DNA, genetic information for building cell

-chromosomes are packaged DNA

-mitochondria: used for converting sugar to energy

-chloroplast: performs photosynthesis, only found in plants

-vacuole: storage closet of cell: acids, pigments, chemicals

-endoplasmic reticulum: site of protein synthesis

-golgi: processes proteins to be exported from cell

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