Molecules and Cells: Biomolecules

Goals: -Describe the roles of the four types of biomolecules (nucleic acids, proteins, carbohydrates, and lipids) -Identify the structural features that define each type of biomolecule

carbohydrates

energy storage/source. class of molecules that range from small sugar molecules, to large polysaccharides

monosaccharide

monomer of carbohydrates

glucose

a common monosaccharide of central importance in life chemistry

glucose molecular formula

C6H12O6

isomer

having the same molecular formula; fructose and glucose molecules are both C6H12O6

What varies molecules that are isomers?

different arrangement of atoms = different properties

Write the formula for a monosaccharide with 3 carbohydrates

C3H6O3

disaccharide

two monosaccharides bonded through dehydration reaction. One monomer gives up a hydroxyl group and the other gives up a hydrogen atom, forming H2O. The remaining oxygen atom links the two monomers together

sucrose

most common disaccharide. Made up of glucose monomer linked to a fructose monomer. Provides a source of energy and raw materials to all the parts of plants

Lactose is the disaccharide sugar in milk. It is formed from glucose and galactose. The formula for both of these monosaccharides is C6H12O6. What is the formula for lactose?

C12H22O11

polysaccharides

polymers of thousands of monosaccharides, linked together by dehydration reactions. Function as storage/structural compounds/molecules

• starch, glycogen, and cellulose

Starch

storage polysaccharide in plants. Long chains of glucose monomers.

• molecules coil into helixal shape and maybe unbranched or branched

glycogen

animals store glucose in a polysaccharide called glycogen. Higher branched then starch

cellulose

most abundant organic compound compound. cellulose is a polymer of glucose. Hydrogen bonds form layers of microfibrils. animals do not have enzymes that can hydrolyze the glucose linkages in cellulose - not a nutrient for humans. Cows can hydrolyze cellulose and thus, able to drive energy from it

chitin

structural polysaccharide used by insects and crustaceans to build their exoskeleton

almost all carbohydrates are…

hydrophillic. - due to many hydroxyl groups attached to sugar monomers

compare and contrast starch and cellulose, two plant polysaccharides

both are polymers of glucose, but the bonds between glucose monomers have different shapes. Starch functions as storage. cellulose is structural polysaccharide that is used for plant cell walls.

lipids

diverse group of molecules with shared trait. they do not mix well with water.

lipids are…

hydrophobic

types of lipids

fats, phospholipids, and steroids

fat

large lipid made from two smaller molecules: glycerol and fatty acids

glycerol

consists of three carbons, each bearing a hydroxyl group (OH)

fatty acids

consists of a carboxyl group (the functional group -COOH), a hydrocarbon chain (16-18 carbon atoms)

• nonpolar C-H bonds in hydrocarbon chains are reason for hydrophobic

fatty acids are…

hydrophobic

what kind of reaction happens that links fatty acids to glycerol?

dehydration reaction

triglyceride

three fatty acids to glycerol

unsaturated fatty acid

hydrogen chain contains one or more double bonds

saturated fatty acid

no double bonds in hydrocarbon chain has max number of hydrogen atoms attached to each carbon

what are the forms of unsaturated and saturated fats at room temperature?

unsaturated: liquid (kinks prevent tight packing)

saturated: solid (packed tight because of no kinks)

trans fat

unsaturated fats are converted to saturated fats by adding a hydrogen.

fat function

energy storage (1g of fat = 2X as much energy as 1g of polysaccharide)

explain why fats are hydrophobic

the three fatty acid tails of a fat molecule contain only nonpolar (C-H) bonds, which do not mix well with polar water molecules

phospholipids

major component of cell membrane. cells can’t live without. structurally similar to fats but only have two fatty acids instead of 3. Also has a negatively charged phosphate group

steroids

lipids with the carbon skeleton containing four fused rings

cholesterol

precursor for making other steroids, including sex hormones

compare the structure of a phospholipid to fat

phospholipid has two fatty acids and phosphate group attached to glycerol. fat has three fatty acids attached to glycerol

prokaryotic cells

first to evolve and are microorganisms in the Bacteria, and Achaea domain of organism groups. Simple and small structures

eukaryotic cells

all other forms of life are in domain eukarya. They have a membrane-enclosed nucleus, housing most of the DNA, and other membrane-enclosed organelles that perform specific functions

Both cells

have cytosol, chromosomes, ribosomes, cytoplasms

cytosol

plasma membrane, the inside of cells is filled with a thick, jellylike fluid

chromosomes

carry genes made up of DNA

ribosomes

tiny structures that make proteins from gene instructions (synthesize proteins)

cytoplasm

the inside of cells (in eukaryotic cells: region between nucleus and plasma membrane)

nucleoid

coiled DNA in a region only in prokaryotic cells-no membrane around DNA

capsule

sticky outer coat on some prokaryotes. some have projections

some capsules have projections. what are the two and explain.

short projections: help attach prokaryotes to each other or their substrate

long projections (flagella): propel a cell through its liquid environment