Bio Lecture 3 and 4 Flashcards
What is a dehydration reaction?
When 2 monomers bond together into a polymer through the loss of a water molecule
What is a hydrolysis reaction?
Polymers are disassembled into monomers by adding a water molecule
What are carbohydrates
Serve as fuel and building material. The simplest carbohydrates are monosaccharides. Carbohydrate macromolecules are polysaccharides which are polymers composed of many sugar building blocks
Explain monosaccharides
Molecular formulas that are usually multiples of CH2O
Glucose is the most common
Have glycosidic linkages
Classified by number of carbons and location of carbonyl group
Explain polysaccharides
Polymers of sugar that have storage and structural roles
Structure and function determined by sugar monomers and position of glycosidic linkages
Give examples of storage polysaccharides
Starch consists entirely of glucose monomers
Glycogen in animals in liver and muscle cells. Hydrolysis of glycogen release glucose when the demand for energy increases
Give examples of structural polysaccharides
Cellulose is a major component of plant cell walls and is a polymer of glucose
Chitin - found in arthropod exoskeletons
Why do the glycosidic linkages of cellulose differ from those of starch
Ring forms of glucose in the 2 polymers are slightly different. Cellulose contains beta glucose instead of alpha glucose in starch
What are lipids?
One class of large biological molecules that does not form polymers. Unifying feature of lipids is little or no affinity for water
Why are lipids hydrophobic?
Because they consist mostly of hydrocarbons which are non polar
Examples of lipids
- fats
- phospholipids
- steroids
What are fats constructed from?
Glycerol and fatty acids
What is glycerol?
A three carbon alcohol with an hydroxyl group attached to each carbon
What do fatty acids consist of??
Carboxyl group linked to a long hydrocarbon chain
Describe fatty acids
Three fatty acids are joined to glycerol by water linkages to form triglyceride
Vary in length, number and location of double bonds
Saturated fatty acids do not have double bonds and are solid at room temp
Unsaturated fatty acids have one or more double bonds and are liquid at room temp
A diet rich in….. may contribute to cardiovascular disease
Saturated fats
Definition of hydrogenation
Process of converting unsaturated fats to saturated fats, creates unsaturated fats with trans double bond. These trans fats may contribute more than saturated fats to cardiovascular disease
What are essential fatty acids?
Certain Unsaturated fatty acids are not synthesized in the human body and must be supplied through diet
Major function of fat
Energy storage
What are phospholipids?
Two fatty acids and a phosphate group attached to glycerol. The two fatty acid rails are hydrophobic and the phosphate head group is hydrophilic
Protein functions include
– Speeding up (catalyzing) chemical reactions
– structural support
– storage
– transport
– cellular communications
– movement
– defense against foreign substances
Receptor proteins
Response of cell to chemical stimuli
polypeptides
Amino acids are linked together into unbranched polymers
Amino acids are
organic molecules with
carboxyl and amino
groups
Amino acids are linked by
peptide bonds
Primary structure
the sequence of amino acids
Secondary structure
Results from hydrogen bonds between repeating constituents
* Typical secondary structures include:
– coil called an α-helix, and
– folded structure called a β-pleated sheet
Tertiary structure
Is the overall shape of a polypeptide, and is determined by interactions between R groups
Quaternary structure
results when two or more polypeptide chains form one macromolecule
Two types of nucleic acids
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Shape of the nucleus is maintained by
nuclear lamina
Components of endomembrane system
– Nuclear envelope
– Endoplasmic reticulum
– Golgi apparatus
– Lysosomes
– Vacuoles
– Plasma membrane
Smooth ER
- Synthesizes lipids
- Metabolizes carbohydrates
- Detoxifies drugs and poisons
- Stores calcium ions
Rough ER
Has bound ribosomes, which synthesize glycoproteins
Produces transport vesicles, which distribute lipids and proteins to other
components of the endomembrane system
Lysosome
membrane-bound compartment of
hydrolytic enzymes that can digest macromolecules
* Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids
* Lysosomal enzymes work best in acidic environment inside lysosome
phagocytosis
Some cells can engulf
another cell
