Biology Chapter on Macromolecules

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Questions and Answers

What is the primary function of carbohydrates in living organisms?

To release energy during respiration (correct)

To serve as enzymes for biochemical reactions

To store genetic information

To insulate the body against cold

Which type of carbohydrate consists of two monosaccharides joined together?

Monosaccharides

Disaccharides (correct)

Polysaccharides

Oligosaccharides

What is the structural role of cellulose in plants?

To transport nutrients

To support cell walls and maintain shape (correct)

To store energy

To facilitate photosynthesis

What is a characteristic of lipids concerning their solubility?

Insoluble in water but soluble in organic solvents Signup and view all the answers

What do proteins primarily consist of?

Many amino acids Signup and view all the answers

Which molecule serves as a key energy storage compound in animals?

Glycogen Signup and view all the answers

What is the ratio of hydrogen to oxygen in carbohydrates?

2:1 Signup and view all the answers

Which of the following is not a type of lipid?

Polysaccharides Signup and view all the answers

What is a key requirement for active transport to function effectively?

It requires energy. Signup and view all the answers

What does phagocytosis primarily allow cells to do?

Engulf large particles. Signup and view all the answers

During which phase of the cell cycle does DNA duplication occur?

Interphase Signup and view all the answers

What role do chromosomes play in a cell?

They carry and regulate genetic material. Signup and view all the answers

What occurs during the prophase of mitosis?

The nuclear membrane breaks down. Signup and view all the answers

Which is NOT a characteristic of active transport?

It occurs through passive diffusion. Signup and view all the answers

What happens to the chromosomes during metaphase?

They arrange themselves at the spindle equator. Signup and view all the answers

What is formed as a result of phagocytosis after a cell engulfs a large particle?

A phagosome Signup and view all the answers

During which stage of the cell cycle is genetic material dispersed and loosely packed?

Interphase Signup and view all the answers

Which statement is true regarding phagocytosis?

It helps remove pathogens from the immune system. Signup and view all the answers

What initial step is taken before placing the onion epidermis slide on the stage?

Tear off the onion epidermis Signup and view all the answers

Which adjustment knob should be used after switching to the high power objective?

Fine adjustment knob Signup and view all the answers

What is the purpose of using iodine solution on the onion epidermis?

To enhance cell structure visibility Signup and view all the answers

When using the coarse adjustment knob, why is it advised to start with a lower power objective?

To make focusing on the specimen easier Signup and view all the answers

What effect does adjusting the diaphragm have on the visibility of the specimen?

Controls the brightness of the image Signup and view all the answers

What should be done to avoid eyestrain during the observation process?

Keep both eyes open Signup and view all the answers

What characteristic of cells is stated in cell theory?

Cells are the basic unit of structure in living organisms Signup and view all the answers

Which of the following adjustments is NOT necessary when using a lower power objective?

Fine adjustment Signup and view all the answers

Which molecules can easily diffuse across the phospholipid bilayer?

Nonpolar molecules Signup and view all the answers

What is the primary reason ions cannot easily cross the cell membrane?

They are repelled by hydrophobic tails. Signup and view all the answers

What does the fluid-mosaic model describe about cell membranes?

Cell membranes are composed of a mosaic of proteins and lipids. Signup and view all the answers

Which factor would NOT affect the rate of diffusion?

Cell membrane thickness Signup and view all the answers

How does an increase in temperature affect diffusion?

It increases kinetic energy and speeds up diffusion. Signup and view all the answers

Which of the following best describes the role of the carbohydrate chain on a glycoprotein?

Serves a signaling and antigenic function. Signup and view all the answers

What happens to the diffusion rate if the concentration gradient increases?

It increases. Signup and view all the answers

Which size of particles will diffuse faster at the same temperature?

Small molecules Signup and view all the answers

What defines the 'fluid' aspect of the fluid-mosaic model?

Lateral movement of phospholipids Signup and view all the answers

What type of molecule is indicated to pass through the cell membrane by diffusion?

Hydrophobic molecules Signup and view all the answers

What is the primary site of glycolysis in cellular respiration?

Cytoplasm Signup and view all the answers

Which process generates the highest amount of ATP in aerobic respiration?

Oxidative phosphorylation Signup and view all the answers

During anaerobic respiration, which of the following is a common product generated by yeast?

Ethanol Signup and view all the answers

What key compound is formed from pyruvate in the Krebs cycle?

Acetyl CoA Signup and view all the answers

Which of the following statements about the Krebs cycle is correct?

It produces NADH and FADH. Signup and view all the answers

What is the primary role of anaerobic bacteria in sewage treatment?

Decompose organic matter into inorganic matter Signup and view all the answers

What is a consequence of fermentation in anaerobic respiration?

Generation of ethanol or lactic acid Signup and view all the answers

Which compound is utilized for energy during glycolysis?

ATP Signup and view all the answers

Which component is not directly involved in the Krebs cycle?

Glucose Signup and view all the answers

Which of the following processes does not rely on anaerobic respiration?

Photosynthesis Signup and view all the answers

What is produced during the carbon fixation phase of the Calvin cycle?

3-C compounds Signup and view all the answers

Which molecule provides reducing power for the conversion of 3-C compounds to glucose?

NADPH Signup and view all the answers

In the overall photosynthesis equation, what are the reactants needed to produce glucose?

Carbon dioxide, water, and light Signup and view all the answers

How many molecules of ATP are required to regenerate the carbon dioxide acceptor in the Calvin cycle?

6 Signup and view all the answers

Which of the following is NOT a product of photosynthesis?

NADPH Signup and view all the answers

What happens during the reduction phase of the Calvin cycle?

3-C compounds are converted to triose phosphate Signup and view all the answers

Which two products of the Calvin cycle can be used to form storage molecules within the plant?

Glucose and glycerol Signup and view all the answers

Which process is primarily responsible for the formation of glucose from carbon dioxide during photosynthesis?

Calvin cycle Signup and view all the answers

What is the end product of combining two molecules of triose phosphate in the Calvin cycle?

6-C compound Signup and view all the answers

Which statement about photosynthesis products is incorrect?

Fatty acids can be converted to glucose. Signup and view all the answers

Study Notes

Cellular Biology

Cells are the fundamental units of all living organisms
All living organisms are composed of one or more cells
Cells are the basic unit of structure and organization in organisms
Cells arise from pre-existing cells

Molecules of Life

Carbohydrates are made up of C, H, and O (H:O = 2:1)
Types of carbohydrates include monosaccharides (e.g., glucose, fructose), disaccharides (e.g., maltose, sucrose), and polysaccharides (e.g., starch, glycogen, cellulose)
Lipids are made up of C, H, and O (H:O > 2:1)
Types of lipids include triglycerides, steroids, and phospholipids
Proteins are made up of amino acids with C, H, O, N (sometimes S)
Proteins have various functions, including structural components, enzymes, and energy sources
Nucleic acids (e.g., DNA, RNA) are made up of C, H, O, N, and P
Water is the most abundant substance in living cells, acting as a solvent, cooling agent, and raw material for photosynthesis
Minerals are inorganic ions, such as calcium, phosphate, iron, magnesium, and nitrate

Cells – Cell Theory

All living organisms are composed of one or more cells
The cell is the basic unit of structure and organization in organisms
Cells arise from pre-existing cells

Cell – Animal Cell

Nucleus: controls cellular activities, stores genetic information, and is involved in protein synthesis
Cell membrane: selectively permeable and allows movement and transport of materials
Cytoplasm: holds many cell organelles and is the site for enzymatic reactions
Mitochondrion: generates energy through aerobic respiration, abundant in root hair cells & secretary cells
Rough endoplasmic reticulum: synthesizes and modifies proteins, abundant in secretary cells
Smooth endoplasmic reticulum: manufactures lipids, detoxes substances
Ribosomes: synthesize proteins

Cell – Plant Cell

Nucleus: controls cellular activities, stores genetic information, and is involved in protein synthesis, but smaller and peripherally placed
Cell wall: freely permeable, and contains water and dissolved mineral salts
Vacuole: stores cell sap, contains water and dissolved mineral salts
Chloroplast: carries out photosynthesis
Mitochondria: generates energy
Chloroplasts: carry out photosynthesis

Cell – Prokaryotic Cell

No nucleus
No mitochondria
Have cell walls
Have nucleic acids as genetic material
Have cell membranes
Have cytoplasm

Cell – Cell Membrane

Selectively permeable membrane
Composed of a phospholipid bilayer with embedded protein molecules
Some proteins act as antigens for cell recognition, enzymes, carriers for substances across membrane

Cell – Level of Organization

Cells → tissues → organs → systems → organisms

Movement of Substances Across the Membrane – Diffusion

Diffusion is the net movement of molecules from a region of high concentration to a region of low concentration, driven by kinetic energy
Factors affecting the rate of diffusion include temperature and concentration gradient

Movement of Substances Across the Membrane – Osmosis

Osmosis is the diffusion of water across a selectively permeable membrane from a region of high water potential to a region of low water potential.
Factors affecting the rate of osmosis include temperature and difference in water potential

Movement of Substances Across the Membrane – Active Transport

Active transport moves substances against the concentration gradient, from a region of low concentration to a region of high concentration and requires energy and carrier proteins.

Movement of Substances Across the Membrane – Phagocytosis

Phagocytosis is a process by which a cell engulfs a large particle by extending its plasma membrane to form a phagosome

Cell Cycle & Cell Division - Mitosis

Mitosis is a type of cell division that results in two identical daughter cells with the same number of chromosomes as the parent cell.

Cell Cycle & Cell Division - Meiosis

Meiosis produces four genetically unique haploid daughter cells from one diploid parent cell

Differences between Mitosis & Meiosis

Mitosis involves one division only, whereas meiosis involves two divisions
The daughter cells produced by mitosis are genetically identical to the parent cell.
The daughter cells formed from meiosis contain only half the genetic content of the parent cell

Metabolism - Catabolism and Anabolism

Catabolism is the breakdown of complex molecules to release energy, e.g digestion of starch by amylase
Anabolism is the synthesis of complex molecules from simpler molecules using energy, e.g production of lipase in the pancreas .

Metabolism – Enzymes

Enzymes are biological catalysts that speed up the rate of chemical reactions in metabolism without being used up themselves
Enzyme properties: lower the activation energy of a reaction / reactions are reversible / enzyme is specific / enzyme has active sites /reusable

Metabolism- Factors Affecting Enzyme Reactions

Factors like temperature, pH, and substrate concentration affect the rate of enzyme-catalyzed reactions

Metabolism – Inhibitors

Competitive Inhibitors are similar to the substrate molecules; compete for active sites; rate of reaction increases to the same levels observed without inhibitors
Non-competitive Inhibitors are not similar to the substrates, bind with the enzyme at a different site/allosteric site. affecting the catalytic properties/activity cannot be overcome by increasing substrate concentration

Experiments with Enzymes

Experiments demonstrating enzyme activity can involve observing changes in colour, size, or the presence of precipitates.

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Description

Test your knowledge on the primary functions and structures of carbohydrates, lipids, and proteins in living organisms. This quiz covers key concepts such as energy storage and the roles of different macromolecules in nature.