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My report on "Lipids and Carbohydrates"
My report on "Lipids and Carbohydrates"
Student name: Giulia Baldon
Teacher name: Perroteau
School: university of Torino
Submission Time: 10/10/09 16.57
Page 1 : http://mw2.concord.org/public/part2/lipidcarb/page1.cml
Page 2 : http://mw2.concord.org/public/part2/lipidcarb/page2.cml
Page 3 : http://mw2.concord.org/public/part2/lipidcarb/page3.cml
Page 4 : http://mw2.concord.org/public/part2/lipidcarb/page4.cml
Page 5 : http://mw2.concord.org/public/part2/lipidcarb/page5.cml
Page 6 : http://mw2.concord.org/public/part2/lipidcarb/page6.cml
1. Which statement about membrane phospholipids is NOT true?
(a) They associate to form bilayers.
(b) They have hydrophobic "tails."
(c) They have hydrophilic "heads."
(d) They allow certain materials to pass by them.
(e) They move easily from one side of the membrane to the other.
My answer is (e) (16.55.56)
2. Membranes can keep chemicals inside and outside of the cell. What would happen if a cell membrane breaks?
La rottura della membrana cellulare comporta la morte della cellula (lisi). (16.56.33)
Page 7 : http://mw2.concord.org/public/part2/lipidcarb/page7.cml
1. How is the lipid molecule different from the sugar molecule? (check all that apply.)
(a) Lipids have more oxygen than the sugars
(b) Sugars have more oxygen than the lipids
(c) Sugars contain two hydrogen atoms for every oxygen.
(d) Lipids contain two hydrogen atoms for every oxygen.
My answer is (b) (c) (16.20.21)
2. An increase in the ratio of oxygen atoms to hydrogen and carbon... (check all that are true)
(a) increases the separation of surface charge
(b) decreases the separation of surface charge
(c) makes the molecule polar
(d) makes the molecule nonpolar
My answer is (a) (c) (16.20.53)
3. Select a snapshot image that shows benzene molecules do not mix well with water molecules.
(16.28.19)
4. Fill in a snapshot image that shows glucose molecules mix better with water molecules.
(16.28.26)
5. Explain how the presence of the OH groups affects the solubility and properties of glucose.
La presenza del gruppo OH influisce sulla solubilità del glucosio poichè interagisce con la molecola d'acqua grazie alla propria polarità. L'H del glucosio verrà attratto dall'O della molecola d'acqua come l'ossigeno del glucosio verrà attratto dall'idrogeno di H2O (16.31.15)
Page 8 : http://mw2.concord.org/public/part2/lipidcarb/page8.cml
1. Cellulose is made of long polysaccharide chains that line up in parallel. How does this structure relate to its function?
La struttura è legata soprattutto alla funzione della parete cellulare che è di struttura. (16.38.01)
2. Long linear polysaccharides make strong fibers because:
(a) The polysaccharide molecules are strong molecules.
(b) The carbon backbone makes the polysaccharide strong.
(c) Aligning many linear molecules next to each other makes it hard to bend them.
(d) The chains that align closely have many hydrogen bonds along the chain making it hard to break apart.
My answer is (d) (16.39.23)
Page 9 : http://mw2.concord.org/public/part2/lipidcarb/page9.cml
1. Branched polysaccharides can be more easily separated into individual chains than linear polysaccharides like cellulose. This is explained by:
(a) the tight fit that can occur between branched molecules.
(b) the increased number of covalent bonds in linear chains.
(c) the increased number of weak interactions that can form between branched chains.
(d) the increased number of weak interactions that can form between linear chains.
My answer is (d) (16.41.19)
2. Based on your observations of the polysaccharides in the models, explain why starch is edible and wood is not.
L'amido è digeribile poichè presentandosi sotto forma di polisaccaride "ramificato" le sue catene sono più semplici da separare quindi più facilmente digeribili dal corpo umano. (16.44.18)
Page 10 : http://mw2.concord.org/public/part2/lipidcarb/page10.cml
1. Which substance produces chemical energy more quickly, starch or glycogen, when enzymes work on it? Why? (❏ Hint)
Il glicogeno poichè possiede più rami al termine dei quali è presente il glucosio. Gli enzimi, attaccandosi alle terminazioni dei rami liberano velocemente glucosio. (16.49.18)
2. Which substance would produce more chemical energy if enzymes could attack in the middle of the chain rather than just at the ends?
L'amido. (16.48.17)
Page 11 : http://mw2.concord.org/public/part2/lipidcarb/page11.cml
1. In the model to the left, three molecules tagged as "A", "B" and "C" are placed in water. Click the "" button to run the model and observe what happens. Based on your observation, can you tell which molecule is the most polar?
(a) Molecule A.
(b) Molecule B.
(c) Molecule C.
My answer is (a) (16.50.23)
2. Compare two hydrocarbon chains: one with oxygen atoms and one without. How does the presence of oxygen affect the properties of a hydrocarbon chain?
(a) Makes them polar.
(b) Makes them non-polar.
(c) Makes them soluble in oil.
(d) Makes them chemically transparent.
My answer is (a) (16.50.35)
3. What makes cellulose so strong?
(a) Cellulose is a linear polysaccharide that is strongly attracted with hydrogen bonds to other linear polysaccharides.
(b) Cellulose is made of a combination of fatty acids and phospholipids surrounded by polysaccharides.
(c) Cellulose is a branching polysaccharide that is strongly attracted to other branching polysaccharides.
(d) Cellulose is a combination of linear and branching polysaccharides that strongly attract to each other.
My answer is (a) (16.51.05)
4. Describe why lipids are so important to cellular evolution.
Sono importanti perchè rivestono il fondamentale ruolo di componenti delle membrane cellulari. (16.57.10)
5. Table sugar and wood are both made of glucose. Why can you serve cubes of sugar with tea, but not cubes of wood (without offending your guests)?
Lo zucchero è solubile ma soprattutto commestibile, mentre il legno non lo è. (16.54.30)
6. Which statement about membrane phospholipids is NOT true?
(a) They associate to form bilayers
(b) They have hydrophobic "tails"
(c) They have hydrophilic "heads"
(d) They make the membrane rigid
My answer is (d) (16.51.45)
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