The Cell as the Basic Unit of Life

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Questions and Answers

What is the primary role of nitrate in plants?

A component of chlorophyll

A regulator of enzyme activity

A source of nitrogen for the synthesis of proteins (correct)

A source of phosphorus for root growth

Which of the following statements accurately describes the function of calcium in animals?

It helps strengthen cell walls

It is involved in muscle contraction and blood clotting (correct)

It is a key component of red blood cells

It enhances digestive enzyme activity

Which inorganic ion is necessary for the synthesis of hemoglobin in animals?

Iron (correct)

Calcium

Magnesium

Nitrate

What role does magnesium play in both animals and plants?

Activates some enzymes Signup and view all the answers

Which of the following best describes the function of phosphate in animals?

A component of bones and teeth Signup and view all the answers

In plants, which ion is crucial for forming nucleic acids?

Phosphate Signup and view all the answers

What is NOT a function of iron in animals?

Forms part of bone structure Signup and view all the answers

Which of these inorganic ions is involved in strengthening cell walls in plants?

Calcium Signup and view all the answers

What role does water play in providing support to plant cells?

It maintains cell shape through turgidity. Signup and view all the answers

Which of the following statements accurately describes the function of pleural fluid?

It reduces friction between the lungs and thoracic cavity. Signup and view all the answers

In what way do inorganic ions function in organisms?

They are involved in various physiological functions. Signup and view all the answers

How does the turgidity of plant cells facilitate the standing upright of seedlings?

It creates pressure against the cell wall, providing structure. Signup and view all the answers

Which property of water contributes to its ability as a lubricant in biological systems?

Its viscosity and surface tension. Signup and view all the answers

What percentage of body weight does water typically constitute in humans?

60% Signup and view all the answers

Which of the following is NOT a function of water in organisms?

Aspiration of oxygen Signup and view all the answers

In plants, water helps transport inorganic ions predominantly through which process?

Transpiration Signup and view all the answers

Which chemical equation illustrates a process that involves water as a reactant?

6CO2 + 6H2O → C6H12O6 + 6O2 Signup and view all the answers

What role does water play as a cooling agent in organisms?

It removes heat during evaporation. Signup and view all the answers

Why is the ability of water to dissolve many substances important for organisms?

It facilitates metabolic reactions. Signup and view all the answers

What happens to body temperature when humans produce more sweat?

It decreases as sweat evaporates. Signup and view all the answers

What is the main component that contributes about 98% of the body weight in organisms like jellyfish?

Water Signup and view all the answers

Which of the following biomolecules is primarily known for containing both carbon and nitrogen?

Nucleic acids Signup and view all the answers

What element is a primary component of all major organic substances?

Carbon Signup and view all the answers

Which carbohydrate is primarily used as an energy source in cells?

Glucose Signup and view all the answers

What is the role of phospholipids in biological systems?

Cell membrane structure Signup and view all the answers

Which of these pairs correctly matches the type of biomolecule with its example?

Carbohydrate - Starch Signup and view all the answers

Which of the following best describes nucleic acids?

Polymers of nucleotides Signup and view all the answers

Which element is NOT a primary constituent of carbohydrates?

Nitrogen Signup and view all the answers

Which characteristic distinguishes biomolecules from inorganic compounds?

Presence of carbon Signup and view all the answers

What is the maximum magnification achievable with light microscopes?

Which type of microscope produces a three-dimensional image?

Scanning electron microscope (SEM) Signup and view all the answers

What color is generally produced by light microscopes?

Coloured image Signup and view all the answers

Which of the following microscopes uses electron beams to form images?

Scanning electron microscope (SEM) Signup and view all the answers

What is the primary characteristic of images produced by transmission electron microscopes (TEM)?

They are two-dimensional and show internal structures. Signup and view all the answers

What type of image do most electron micrographs in scientific literature appear as due to additional processing?

False color Signup and view all the answers

Which microscope offers a maximum magnification of 1,500,000 times?

Transmission electron microscope (TEM) Signup and view all the answers

What is a significant limitation of light microscopes compared to electron microscopes?

They have lower maximum magnification. Signup and view all the answers

Study Notes

Inorganic Chemical Constituents of Organisms

Water accounts for about 60% of body weight in humans and even more in organisms like jellyfish.
Functions of water:
- Acts as a reactant in chemical reactions, e.g., photosynthesis.
- Serves as a medium for dissolving substances and facilitating chemical reactions.
- Functions as a cooling agent by removing heat during evaporation (e.g., sweat).
- Provides support by maintaining turgidity in plant cells, helping seedlings stand upright.
- Major component of lubricating fluids, reducing friction (e.g., pleural fluid in lungs).

Inorganic Ions

Inorganic ions, often termed minerals, play essential roles in both plants and animals.
Key inorganic ions and their functions:
- Nitrate: Source of nitrogen for protein synthesis.
- Magnesium: Activates enzymes and is a component of chlorophyll in plants.
- Iron: Essential for forming hemoglobin in red blood cells for oxygen transport.
- Calcium: Key for bone and teeth structure; involved in blood clotting and muscle contraction.
- Phosphate: Component of bones, phospholipids, and nucleic acids (e.g., DNA).

Organic Chemical Constituents of Organisms

Major organic substances include carbohydrates, lipids, proteins, and nucleic acids, collectively known as biomolecules.
Carbohydrates are composed of carbon, hydrogen, and oxygen, with common types being:
- Glucose: Main energy source for cellular functions.
- Starch: Energy storage in plants.
- Glycogen: Energy storage in animals.
- Cellulose: Structural component in plant cell walls.

Microscopy Techniques

Light Microscopes: Uses light to pass through samples, achieving magnifications of up to 1600 times with colored images.
Electron Microscopes: Utilize electron beams for higher magnifications:
- Scanning Electron Microscopes (SEM): Offer three-dimensional images showing external structures (up to 500,000 times).
- Transmission Electron Microscopes (TEM): Provide two-dimensional images of internal structures (up to 200,000 times).
Most electron micrographs are in black and white, but false color can be added digitally for better visualization.

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Description

Explore the foundational concepts of cells, focusing on their role as the basic unit of life. This quiz highlights the importance of inorganic chemical constituents such as water and ions in biological organisms. Test your knowledge on how these components support cellular functions.