Carbs And Lipids

Question 1

What is the definition of a monomer

Answer 1

Small single units that act as the building blocks to create larger molecules

Question 2

Polymers definition:

Answer 2

Made up of two or more monomers that are chemically bonded together

Question 3

Condensation reaction :

Answer 3

When two molecules join together with the formation of a new chemical bond and a water molecule is released when the bond is formed

Question 4

Hydrolysis reaction definition

Answer 4

It breaks the chemical bond between monomers using a water molecule

Question 5

What is the purpose of carbohydrates

Answer 5

-to store energy in both plants and animals
-to provide structural support to plant cells

Question 6

What are examples of monosaccharides

Answer 6

-glucose
-fructose
-galactose

Question 7

What are examples of disaccharides

Answer 7

-maltose
-sucrose
-lactose

Question 8

What are examples of polysaccharides

Answer 8

-cellulose
-starch
-glycogen

Question 9

What is the general formula for a monosaccharide

Answer 9

CnH2nOn

Question 10

Glucose + glucose =

Answer 10

Maltose

Question 11

Glucose+galactose=

Answer 11

Lactose

Question 12

Glucose+fructose=

Answer 12

Sucrose

Question 13

Describe the structure of starch glycogen and cellulose

Answer 13

Starch is made up of two types of molecules: amylose and amlopectin
amylose has long straight unbranched a1-4 glycosidic bonds. whereas amylopectin has this aswell as short branched a1-6 glycosidic bonds.

Glycogen is more branched than starch but also has a1-4 and a1-6 glycosidic bonds between alpha glucoses

Cellulose has long staright unbranched chains of beta glucose with b1-4 glycosidic bonds
with many weak hydrogen bonds between them to form microfibrils

Question 14

Structure of starch

Answer 14

-starch is made up of two polymers amylose and amylopectin
-amylose is spiral shaped and is joined together by 1,4 glycosidic bonds
-amylopectin is joined by both 1,4 and 1,6 glycosidic bonds
-the 1,6 glycosidic bonds are branched that’s why starch is branched

Question 15

Properties of starch

Answer 15

-insoluble :so water potential of the cell won’t change and is osmotically inactive
-spiral shaped so it very compact
-branched chains so provides a large surface area

Question 16

Where is glycogen stored

Answer 16

Liver and muscle cells

Question 17

Why Is glycogen more branched than starch

Answer 17

Has more 1,6 glycosidic bonds

Question 18

Benedict’s test for a reducing sugar

Answer 18

-add Benedict’s reagent to a sample and heat in a water bath for 5 minutes
-if it turns to a brick red precipitate then there is a reducing sugar present

Question 19

Benedict’s test: non reducing sugar

Answer 19

-perform the benedicts test to confirm a negative result
-add acid (HCl) then heat in a water bath
-then add equal parts of alkaline solution (NaOH ) to naturalise.
-add Benedict’s reagent again and heat in a water bath
-if a non reducing sugar is present u should get a brick red ppt

Question 20

Test for starch

Answer 20

-Iodine test
-add iodine solution
-if starch is present sample will change from orange/yellow to blue/black

Question 21

Structure and function of glycogen

Answer 21

-has many side branches so stored glucose can be released quickly which is imprtant for energy release in animals
-very compact so can store more glucose

Question 22

Give a function of glycogen and its purpose

Answer 22

-short chains: leads to glycogen being more rapidly hydrolysed into glucose for respiration
-more highly branched: larger SA
-insoluble : does not affect WP or diffuse out of cells

Question 23

Explain one way in which starch molecules are adapted for their function in plant cells

Answer 23

-Insoluble: so does not affect WP
-helical: more compact
-large molecule : can’t leave the cell

Question 24

Describe how the structure of cellulose is related to its function in plants

Answer 24

Cellulose is long straight unbranched chains of beta glucose joined together by many weak hydrogen bonds to form microfibrils which provide strength and rigidity to the cell wall

Question 25

Describe how you would produce a calibration curve for a reducing sugar of unknown concentration and use it to obtain results

Answer 25

-make up several known concentrations of reducing sugar (maltose/lactose/galactose/ fructose) -Carry out the Benedict test on each sample -Use a colourimeter to measure the colour intensity of each solution and plot a calibration curve -known conc on x axis and absorbance on y axis -find the concentration of the unknown sample using the calibration curve

Question 26

What is an unsaturated fatty acid?

Answer 26

Double bonds between carbon atoms within the hydrocarbon chain

Question 27

Give two features that help triglycerides to function as a storage molecule

Answer 27

-long hydrocarbon tails -insoluble -high ratio of hydrogen to oxygen atoms

Question 28

Describe the induced fit model and explain how it acts as a catalyst

Answer 28

Substrate has a complementary shape to the enzyme so binds to form an esc. Active site is alerted to for the substrate. And activation energy is reduced

Question 29

Suggest and explain a procedure the scientists could have done to stop the reaction at each time

Answer 29

Add a strong acid/alkali or boil Which denatures enzyme (atp synthase)

Question 30

Explain how the active site of an enzyme helps to increase the rate of reaction

Answer 30

Substrate has a complimentary shape to the enzyme so binds to form enzyme substrate complex. Active site changes shape to fit substrate. Distorts bonds. Lower activation energy

Question 31

Describe two ways in which dipeptides are similar and different

Answer 31

Similar: -both have amine groups at the end -both have carboxyl groups at the end Difference: Different R-groups