Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
|
Carbohydrate |
-AKA sugar -monomers: monosaccharides (simple sugars) -small polymers: oligosaccharides -large polymers: polysaccharides -chemical formula: (CH2O)n -"n" refers to number of "carbohydrate groups"--can vary from 3 to over a thousand |
|
|
Why can the name of carbohydrates be misleading? |
-carbohydrates don't consist of carbon atoms bonded to water molecules -they are molecules with a carbonyl (C=O) and several hydroxyl (-OH) functional groups, along with several to many carbon-hydrogen (C-H) bonds |
|
|
Carbonyl Groups |
C=O |
|
|
Hydroxyl Groups |
-OH |
|
|
What distinguishes one monosaccharide from another? |
-location of their carbonyl group -variation in carbon number -spatial arrangement of atoms--particularly the relative positions of hydroxyl (-OH) groups -alternative ring forms |
|
|
Naming of 3-carbon, 5-carbon, 6-carbon sugars? |
-3: trioses -5: pentoses -6: hexoses |
|
|
Monosaccharide forms: Carbonyl group at either end of molecule 2 forms? |
-aldose: carbonyl group at either end of carbon chain -ketose: carbonyl group in middle of carbon chain |
|
|
Complex Carbohydrates |
-simple sugars covalently linked into chains of varying lengths |
|
|
Disaccharide |
-when only two sugars are linked together |
|
|
When do monosaccharides polymerize? |
-When a condensation reaction occurs between 2 hydroxyl groups, resulting in a covalent interaction called a glycosidic linkage -the inverse reaction, hydrolysis, cleaves these linkages |
|
|
How are glycosidic linkages similar to peptide bonds and phosphodiester linkages in proteins and nucleic acids? |
--they hold monomers together |
|
|
How are glycosidic linkages different from peptide bonds and phosphodiester linkages? |
-peptide bonds, phosphodiester linkages form b/t the same locations in their monomers, giving proteins & nucleic acids a standard backbone structure -because glycosidic linkages form b/t hydroxyl groups, and because every monosaccharide contains at least 2 hydroxyls, the location & geometry of glycosidic linkages can vary widely among polysaccharides |
|
|
Starch |
-in plant cells, some monosaccharides stored for later use in the form of starch -consists entirely of alpha-glucose monomers joined by glycosidic linkages |
|
|
What two polysaccharides mix to form starch? |
-Amylose: unbranched molecule which contains only alpha-1, 4-glycosidic linkages -amylopectin: branched molecule |
|
|
Glycogen |
-performs same storage role in animals that starch performs in plants |
|
|
Cell Wall |
-protective sheet that occurs outside the membrane -In plants, bacteria, fungi, and many other groups, cell wall is composed primarily of 1/more polysaccharides -In plants, cellulose = major component of cell wall |
|
|
Cellulose |
-structural polysaccharide in plants -major component of cell wall in plants -polymer of beta-glucose monomers, joined by beta-1, 4-glycosidic linkages |
|
|
Chitin |
-polysaccharide that stiffens cell walls of fungi -most important component of external skeletons of insects and crustaceans |
|
|
How do the cell wall in bacteria differ from cell wall in plants? |
-bacteria rarely has ability to produce cellulose -instead, polysaccharide peptidoglycan gives bacterial cell wall strength, firmness |
|
|
What is the most abundant organic compound on earth? What is the second most abundant by weight? |
-most abundant = cellulose -second most by weight: chitin |
|
|
What do carbs do? |
-Precursors to larger molecules: -serve as substrate for synthesizing more complex molecules (eg sugar acts as a subunit of monomers in RNA and DNA) -frequently involved as building blocks in the synthesis of important molecules -provide fibrous structural materials -indicate cell identity -store chemical energy |
|
|
Carbs: structural support |
-create a "tough sheet" able to withstand tension: cellulose, chitin, peptidoglycan form long strands & bonds can form b/t adjacent strands -structural carbs = durable: few organisms have enzymes capable of hydrolyzing cellulose, chitin, peptidoglycan--resistant to degradation or decay |
|
|
Role of Carbs in cell identity: How does structural identity play role? |
-complex carbs can exhibit enormous structural diversity--as result, cable of displaying info to other cells through their structure --polysaccharides act as "identification badge" on outer surface of plasma membrane that surrounds cell |
|
|
Role of Carbs in cell identity:How does structural identity play role? What are glycoproteins? |
-protein that has 1/more carbs covalently bonded -project outward from cell surface into surrounding environment |
|
|
Role of Carbs in cell identity:How does structural identity play role? What are glycoproteins important? |
-key molecules in cell-cell recognition, cell-cell signaling -each cell in body has glycoproteins on surface that identify it as part of body --immune cells can distinguish body's cells from foreign cells --each distinct type of cell in multicellular organism (eg nerve cells, muscle cells) display diff set of glycoproteins on surface |
|
|
Carbs and Energy Storage: Photosynthesis |
-plants harvest kinetic energy in sunlight and store it in bonds of carbohydrates -CO2 + H20 + sunlight -----> (CH2O)n + O2, where (CH2O)n represents a carb |
|
|
Why do C-C and C-H bonds have higher potential energy than C-O bonds? |
-C-C & C-H bonds: electrons are shared equally by atoms with low electronegativities -C-O bonds: the highly electronegative oxygen atom holds electrons v tightly |
|
|
Analogy of relationship b/t carbs, ATP? |
-Carbs: water that piles up behind dam -ATP: electricity generated at a dam, which lights up your home *CARBS STORE CHEM ENERGY; ATP MAKE CHEM ENERGY USEFUL TO CELL |
