Biology Chapter on Water Functions

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Questions and Answers

What percentage of the cells in the body is composed of water?

50% to 70%

40% to 60%

60% to 80% (correct)

70% to 90%

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

Acts as a solvent for reactions

Stores electrical energy (correct)

Absorbs and releases heat

Helps transport materials

What term describes molecules that do not readily mix with water?

Electrophilic

Amphipathic

Hydrophobic (correct)

Hydrophilic

How does the polarity of water molecules affect their interactions?

It leads to attraction among charged molecules Signup and view all the answers

Why does water have a high heat capacity?

Because of the weak bonds between molecules Signup and view all the answers

What is the relationship between hydrogen and oxygen in a water molecule?

Oxygen is more electronegative than hydrogen Signup and view all the answers

What is the effect of hydrogen bonding on ice compared to liquid water?

Ice floats because it is less tightly packed Signup and view all the answers

What unusual property of water is demonstrated by its ability to extinguish fire?

Its polar nature Signup and view all the answers

What is the primary function of enzymes in cells?

To speed up the rate of chemical reactions Signup and view all the answers

Which statement accurately describes ATP?

It is the main energy currency in cells Signup and view all the answers

During cellular respiration, what molecules are combined to form ATP?

Glucose and oxygen Signup and view all the answers

What happens to ATP when it releases energy?

It becomes ADP and loses a phosphate group Signup and view all the answers

Which of the following is NOT a common trait of all cells?

Mitochondria Signup and view all the answers

What forms the primary structure of the cell membrane?

Phospholipid bilayer Signup and view all the answers

How do proteins contribute to the function of the cell membrane?

By facilitating selective permeability Signup and view all the answers

What term refers to molecules that are the reactants in an enzyme-catalyzed reaction?

Substrates Signup and view all the answers

What is the primary role of stem cells in the body?

To serve as an internal repair system for tissues Signup and view all the answers

Which of the following statements best describes pluripotent stem cells?

They can differentiate into a variety of cell types Signup and view all the answers

Which system is responsible for providing support and protection to the body?

Skeletal system Signup and view all the answers

What are the main components of the muscular system?

Voluntary and involuntary muscle groups Signup and view all the answers

Which function is NOT performed by the integumentary system?

Producing blood cells Signup and view all the answers

Which of the following is a feature of involuntary muscles?

They perform functions without conscious thought Signup and view all the answers

How many major body systems are there in the human body?

11 Signup and view all the answers

Which system is primarily involved in the exchange of gases?

Respiratory system Signup and view all the answers

Which of the following is NOT a component of the lymphatic system?

Pancreas Signup and view all the answers

What is the primary function of the gastrointestinal system?

Breaking down food for absorption Signup and view all the answers

Which organ is primarily responsible for the regulation of electrolytes and waste elimination?

Kidneys Signup and view all the answers

What structure in the male reproductive system is responsible for producing sperm?

Testes Signup and view all the answers

Which of the following tissues is NOT one of the four main types of tissues in the body?

Chromosomal Signup and view all the answers

What term describes organs that work together with accessory structures to perform specific activities?

Organ systems Signup and view all the answers

Which component is part of the female reproductive system?

Fallopian Tubes Signup and view all the answers

What is the main purpose of the urinary system?

To eliminate waste and regulate bodily functions Signup and view all the answers

What is the main role of osmosis in the movement of water across a membrane?

It allows water to move to an area with higher solute concentration. Signup and view all the answers

What happens to a cell placed in a hypertonic solution?

Water leaves the cell, causing it to shrink. Signup and view all the answers

What is osmotic pressure?

The pressure that develops when two solutions of varying concentrations are separated by a semipermeable membrane. Signup and view all the answers

What defines a hypotonic solution?

It has a decreased solute concentration outside the cell compared to inside. Signup and view all the answers

What is the primary function of aquaporins in a cell?

They allow for the passive transport of water across the membrane. Signup and view all the answers

What occurs during crenation?

The cell loses water and shrinks. Signup and view all the answers

Which statement correctly describes tonicity and osmosis?

Tonicity is about solute concentration, while osmosis is concerned with the flow of water. Signup and view all the answers

What effect does a hypotonic extracellular solution have on a cell?

The cell takes in water, potentially causing it to burst. Signup and view all the answers

Study Notes

Water (H₂O)

Composes 60% to 80% of body cells, serving as a crucial solvent and medium for biological reactions.
Functions include transporting materials, regulating body temperature through heat absorption/release, and acting as a lubricant.
Exhibits polarity, with a slight negative charge on the oxygen side and a slight positive charge on the hydrogen side, attracting charged molecules (hydrophilic).
Hydrophilic molecules mix well with water, while hydrophobic molecules (like fats) do not.
Hydrogen bonds stabilize water's structure, enhancing its heat capacity; water heats and cools slower than air.
Ice is less dense than liquid water, causing it to float.

Enzymes

Proteins that accelerate chemical reactions in cells, vital for biological molecule breakdown and synthesis.
Enzymes only interact with specific substrates, which are reactants in enzyme-catalyzed reactions.

Cellular Respiration and ATP

In mitochondria, glucose and oxygen convert into ATP (adenosine triphosphate), the energy currency of the cell.
ATP consists of a base, sugar, and three high-energy phosphate groups; breaking these bonds releases energy.
When ATP releases energy, it converts to ADP (adenosine diphosphate) which can be recharged by gaining another phosphate.

Overview of Cells

Cells are the fundamental units of life, varying in shape and size based on function (e.g., nerve, blood, muscle cells).
Common traits of cells include a nucleus (except mature red blood cells), cell membrane, organelles, and cytoplasm.

Cell Membrane

Composed largely of a phospholipid bilayer, which prevents hydrophilic substances from crossing.
Contains cholesterol for stability and proteins facilitating selective permeability.
Essential for transporting waste like carbon dioxide to the lungs.

Osmosis

A specific type of passive transport where water moves through a selectively permeable membrane from low to high solute concentration.
Osmotic pressure refers to the force that pulls water towards higher solute concentrations.
Tonicity describes solute concentration: hypertonic (outside higher solute), hypotonic (inside higher solute), isotonic (equal solute levels).
Crenation occurs when cells lose water in a hypertonic solution, while hypotonic solutions can cause cells to burst from excess water intake.

Stem Cells and Regenerative Medicine

Stem cells can divide and form new tissues, aiding in internal repair mechanisms.
They are derived from adult and embryonic sources, with induced pluripotent stem cells representing a recent advancement.
Regenerative medicine explores the potential to grow tissues and organs for replacements.

Body Systems

Eleven major systems interact to perform complex functions:
- Skeletal: Support, protection, and mineral storage.
- Muscular: Voluntary and involuntary muscle groups facilitating movement.
- Integumentary: Skin provides protection, temperature regulation, and sensation.
- Gastrointestinal: Breaks down food, absorbs nutrients, and eliminates waste.
- Urinary: Eliminates waste and regulates water and electrolyte balance.
- Reproductive: Facilitates reproduction and includes male and female organs.

Key Concepts

Cells are the basic building blocks of life, forming tissues, which are composed of similar cell types.
Membranes are sheet-like structures with specific functions, including cutaneous, serous, mucous, and synovial types.
Organs consist of tissues that serve specific functions, and systems consist of organs working together for broader functions.

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Description

Explore the essential roles of water in the human body through this quiz. Understand how water contributes to cellular composition, serves as a solvent, and regulates body temperature. Test your knowledge about the importance of hydration and acid elimination.