Q: During photosynthesis, plants convert carbon dioxide and water into carbohydrates. Which equation correctly represents this process?

$CO_2 + H_2O + \text{sunlight} \rightarrow (CH_2O)_n + O_2$

Question 1

Which of the following best describes the primary function of glycoproteins found on the external surface of animal cells?

Accepted Answer

Glycoproteins are important for cell-cell recognition.

Question 2

Which molecular formula represents carbohydrates, and what does 'n' stand for in this formula?

Accepted Answer

$C_nH_{2n}O_n$, where n is the number of carbon atoms.

Question 3

Which structural feature distinguishes an aldose from a ketose monosaccharide?

Accepted Answer

Aldoses have a carbonyl group at the end of the carbon chain, while ketoses have it in the middle.

Question 4

Which of the following is a correct statement about glycosidic linkages in polysaccharides?

Accepted Answer

Glycosidic linkages are covalent bonds formed between two hydroxyl groups of monosaccharides.

Question 5

Which polysaccharide is primarily used for energy storage in animal cells, and what is its branching frequency?

Accepted Answer

Glycogen; branches occur about once in every 10 monomers.

Question 6

Which of the following best explains why cellulose is difficult for most organisms to hydrolyze?

Accepted Answer

Cellulose contains $\beta$-1,4-glycosidic linkages, which most organisms lack enzymes to break.

Question 7

A scientist is studying a polysaccharide composed of N-acetylglucosamine (NAG) monomers joined by $\beta$-1,4-glycosidic linkages. Which polysaccharide is she most likely studying?

Accepted Answer

Chitin

Question 8

Which process describes the formation of a disaccharide from two monosaccharides?

Accepted Answer

A condensation reaction between two hydroxyl groups forms a glycosidic linkage.

Question 9

Which of the following best describes the role of carbohydrates in cell identity?

Accepted Answer

Carbohydrates attached to proteins and lipids on the cell surface serve as identification tags for cell-cell recognition.

Question 10

During photosynthesis, plants convert carbon dioxide and water into carbohydrates. Which equation correctly represents this process?

Accepted Answer

$CO_2 + H_2O + 	ext{sunlight} ightarrow (CH_2O)_n + O_2$

Question 11

Which enzyme is responsible for hydrolyzing glycogen in animal cells to release glucose?

Accepted Answer

Phosphorylase

Question 12

Which of the following statements about the energy stored in carbohydrates is correct?

Accepted Answer

Carbohydrates store more energy than $CO_2$ because electrons in C-H and C-C bonds have higher potential energy.

Question 13

Which polysaccharide is found in bacterial cell walls and is characterized by alternating monosaccharides joined by $\beta$-1,4-glycosidic linkages and peptide bonds between adjacent strands?

Accepted Answer

Peptidoglycan

Question 14

A patient is unable to digest starch but can digest glycogen. Which enzyme is most likely deficient in this patient?

Accepted Answer

Amylase

Question 15

Which of the following is a correct multi-step pathway for the use of glucose in cellular energy production?

Accepted Answer

$(CH_2O)_n + O_2 + ADP + P_i \rightarrow CO_2 + H_2O + ATP$

Question 16

Which of the following best explains the difference in geometry between $\alpha$-1,4-glycosidic and $\beta$-1,4-glycosidic linkages?

Accepted Answer

In $\alpha$-1,4-glycosidic linkages, the C-1 hydroxyl groups are on the same side of the glucose ring plane, while in $\beta$-1,4-glycosidic linkages, they are on opposite sides.

Question 17

Which of the following is a real-world application of altered glycosylation patterns in cancer therapy?

Accepted Answer

Targeting cancerous cells with protein therapies that recognize altered glycosylated surface molecules.

Question 18

Which of the following is NOT a function of carbohydrates in cells?

Accepted Answer

Catalyzing metabolic reactions as enzymes.

Question 19

Which structural polysaccharide is found in the exoskeletons of insects and crustaceans?

Accepted Answer

Chitin

Chapter 5: An Introduction to Carbohydrates – Structure, Function, and Biological Importance

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