Biology: DNA Structure and Photosynthesis

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Questions and Answers

What is the main difference between the structures of chlorophyll a and b?

The presence or absence of an aldehyde group (correct)

The presence or absence of a methyl group

The number of carbon atoms in their structures

The type of solvent used for extraction

Which of the following is a function of chlorophyll b?

Capturing light energy in the blue region

Producing ATP during photosynthesis

Transferring energy to chlorophyll a (correct)

Direct involvement in primary photochemical reactions

What is the reason for the difference in absorption spectra between chlorophyll a and b?

The wavelength of light used for analysis

The type of solvent used for extraction

The type of spectrophotometer used for analysis

The difference in their chemical structures (correct)

What is the purpose of using a mortar and pestle in the experiment?

To homogenize 10 g of plant leaves Signup and view all the answers

What is the role of chlorophyll a in photosynthesis?

To directly participate in primary photochemical reactions Signup and view all the answers

What is the purpose of using a spectrophotometer in the experiment?

To analyze the chlorophyll concentration Signup and view all the answers

What is the purpose of adding 2 ml of hydrogen peroxide to test tube 1?

To record the reaction rate Signup and view all the answers

Why is high temperature not used to speed up reactions in the body?

Because it would damage cell proteins Signup and view all the answers

What is the role of enzymes in cellular reactions?

To speed up cellular reactions at body temperature Signup and view all the answers

What is the product of the action of an enzyme?

Product Signup and view all the answers

What is the purpose of adding different chemicals to test tubes 1, 2, and 3?

To test the effect of different chemicals on the reaction rate Signup and view all the answers

What would happen if the cellular reactions happen too slowly in a cell?

The cell would die Signup and view all the answers

What is the purpose of enzymes in the body?

To speed up cellular reactions at body temperature Signup and view all the answers

What is the function of enzymes in the cell?

To speed up cellular reactions and remain unchanged Signup and view all the answers

What is the structure formed by the attachment of nucleotides together?

Double helix Signup and view all the answers

What is the primary function of chlorophyll in photosynthesis?

To capture light energy Signup and view all the answers

Which type of chlorophyll is the primary pigment in photosynthetic organisms?

Chlorophyll a Signup and view all the answers

What is the role of chlorophyll b in photosynthesis?

To expand the range of light wavelengths absorbed Signup and view all the answers

In which region of the spectrum does chlorophyll a have a secondary absorption peak?

Red region Signup and view all the answers

What is the light-dependent reaction involved in photosynthesis?

Conversion of light energy into chemical energy Signup and view all the answers

What is the function of chlorophyll a in the light-harvesting complex?

To transfer light energy to other pigments Signup and view all the answers

What is the result of chlorophyll b absorbing light energy?

Transfer of light energy to chlorophyll a Signup and view all the answers

Study Notes

Enzymes and Chemical Reactions

Thousands of chemical reactions occur inside cells every second to maintain cellular function.
If these reactions happen too slowly, the cell may die.
Enzymes speed up cellular reactions at body temperature by providing a favorable environment for reacting molecules to meet.

Enzymes

Enzymes are proteins produced by cells to increase the rate of chemical reactions.
Enzymes remain unchanged by cellular reactions and can be reused by the cell.

Substrate and Product

The chemicals that enzymes act upon are called substrates.
The chemicals produced by the action of an enzyme are called products.

Photosynthesis

Chlorophyll is a vital pigment involved in photosynthesis, capturing light energy for plant growth and development.
Chlorophyll a and chlorophyll b are both pigments involved in the process of photosynthesis.

Chlorophyll a

Chlorophyll a is the primary pigment in photosynthetic organisms.
It plays a central role in capturing light energy and transferring it to other pigments in the light-harvesting complex.
Chlorophyll a has an absorption peak in the blue-violet region (around 430-450 nm) and a secondary peak in the red region (around 660-680 nm).

Chlorophyll b

Chlorophyll b is an accessory pigment that works in conjunction with chlorophyll a to expand the range of light wavelengths that can be absorbed.
Chlorophyll b absorbs light energy and transfers it to chlorophyll a for the initiation of photosynthesis.
Chlorophyll b has a primary absorption peak in the blue region (around 450-470 nm) and a secondary peak in the orange region (around 640-660 nm).

Structure and Function of Chlorophyll a and b

The main difference between chlorophyll a and b lies in their chemical structures.
Chlorophyll a has a methyl (-CH3) group, while chlorophyll b has an aldehyde (-CHO) group instead.
Chlorophyll a is directly involved in the primary photochemical reactions of photosynthesis, while chlorophyll b acts as an accessory pigment.

Experiment: Extraction and Quantification of Chlorophyll

Materials: 10 green plant leaves, mortar and pestle, ethanol, Whatman No 1 filter paper, spectrophotometer.
Methods: Homogenize plant leaves, extract chlorophyll using ethanol/methanol, filter the extract, and analyze the chlorophyll concentration using a spectrophotometer.

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Description

This quiz covers the structure of DNA and its double helix formation, as well as the importance of chlorophyll in photosynthesis and its role in plant growth and development.