2A2 Levels of Biological Organization

Question 1

What is tissue?

Answer 1

A group of specialized cells that perform the same function and have a similar structure.

Question 2

What is the study of tissues commonly known as?

Answer 2

Histology

Involves the study of tissues, involving their preparation, analysis, and examination under a microscope.

Question 3

What are the four basic tissues in an animal body?

Answer 3

• Epithelial tissue
• Connective tissue
• Muscular tissue
• Nervous tissue

Each tissue type has distinct structures and functions, for example, epithelial tissue covers surfaces, while nervous tissue transmits signals.

Question 4

What is epithelial tissue comprised of?

Answer 4

Sheets of epithelial cells that are in contact with each other.

Question 5

What are the functions of epithelial tissue in the body?

Answer 5

• Covering the external surfaces of the body.
• Lining the internal cavities.
• Forming and lining various organs and glands.

Question 6

How are epithelial cells categorized based on their shape and layers?

Answer 6

• Shape:
  
  • Simple squamous (single layer, flat cells)
  • Cuboidal (cube-shaped)
  • Columnar (taller than wide)
• Layers:
  
  • Simple (one layer)
  • Stratified (multiple layers)

Question 7

What is connective tissue made up of?

Answer 7

A matrix comprised of cells and extracellular material.

The extracellular material, also known as the extracellular matrix, includes fibers like collagen and elastic fibers, and a ground substance that can be fluid, gel-like, or solid.

Question 8

What are the two types of connective tissue?

Answer 8

• Dense connective tissue: thick, densely packed collagen fibers.
• Loose connective tissue: loose, irregularly arranged fibers.

Question 9

What are the three types of muscle tissues in animals?

Answer 9

• Skeletal muscle (voluntary)
• Cardiac muscle (involuntary)
• Smooth muscle (involuntary)

Question 10

What are the muscle fibers comprised of?

Answer 10

Two contractile protein filaments: actin and myosin.

These filaments interact to cause muscle contraction through a process called the sliding filament theory.

Question 11

What type of control are smooth and cardiac muscle fibers under?

Answer 11

Involuntary control.

Question 12

What are the two main parts of nervous tissue?

Answer 12

• Central nervous system (CNS)
• Peripheral nervous system (PNS)

Question 13

What are the two contractile protein filaments found in myofibrils?

Answer 13

1. Actin
2. Myosin

Question 14

What are the two major tissues in plants?

Answer 14

• Meristematic tissue
• Permanent tissue

Meristematic tissue is involved in plant growth.

Permanent tissue includes differentiated cells that perform specific functions.

Question 15

What are the two categories of permanent tissues in plants?

Answer 15

• Simple tissues
• Complex tissues

Question 16

What are the three tissue systems in plant permanent tissue?

Answer 16

1. Dermal tissue
2. Ground tissue
3. Vascular tissue

Question 17

What is the function of phloem in plants?

Answer 17

Transport food in a process called translocation.

Phloem primarily transports sugars and other metabolic products downward from the leaves.

Question 18

What is the function of xylem in plants?

Answer 18

Transports water in a process known as transpiration.

Xylem also transports mineral ions from the soil to the rest of the plant and provides structural support.

Question 19

What is an organ system?

Answer 19

A collection of organs working together toward a common goal.

Organ systems include multiple organs, but organs may be involved in more than one organ system.

E.g. The digestive system.

Question 20

What does the integumentary system include and what is its main function?

Answer 20

• Includes: skin, nails, and hair.
• Main function: Protect the body.

Question 21

What are the main components and functions of the skeletal system?

Answer 21

• Components: bones, joints, and cartilage.
• Functions: Provides structure, support, and facilitates movement.

Bones also produce blood cells and store minerals like calcium and phosphorus.

Question 22

What are the main components and functions of the circulatory system?

Answer 22

• Components: heart, blood vessels, and blood.
• Functions: Transport oxygen, nutrients, and remove waste.

The heart pumps blood through the blood vessels to the body.

Question 23

What is the main function of the respiratory system?

Answer 23

To carry out gas exchange.

Air enters the lungs through the nose and mouth and travels to the alveoli for gas exchange.

Question 24

What are the main components and function of the nervous system?

Answer 24

• Components: brain, spinal cord, and nerves.
• Function: Facilitates communication throughout the body.

The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS), with the CNS processing information and the PNS transmitting signals.

Question 25

What is the main function of the **urinary/excretory system**?

Answer 25

To remove metabolic waste from the body and regulate water homeostasis. ## Footnote The kidneys filter waste from the blood to produce urine.

Question 26

What is the main function of the **digestive system**?

Answer 26

To break down food and absorb nutrients into the bloodstream. ## Footnote The digestive system includes organs like the mouth, esophagus, stomach, intestines. Digestion involves both mechanical processes, like chewing, and chemical processes, like enzyme activity.

Question 27

What are the main components & function of the **reproductive system**?

Answer 27

* **Components**: * In **males**: testes and penis. * In **females**: the ovaries, uterus, and vagina. * **Function**: Enables reproduction. ## Footnote The reproductive system also includes structures and hormones that support the development of offspring.

Question 28

What is the main purpose of the **lymphatic system**?

Answer 28

Protects the body from pathogens and maintains fluid homeostasis.

Question 29

What is the function of the **endocrine system**?

Answer 29

* Composed of glands that produce hormones that regulate body functions. * Maintains homeostasis between organ systems.

Question 30

How do body systems and functions interact?

Answer 30

They are interdependent and require coordinated communication.

Question 31

Give an example of **interdependence** between body systems.

Answer 31

* Circulatory system moves blood from the body to the lungs. * Lungs remove carbon dioxide from the blood.

Question 32

What is the function of **connective tissue**?

Answer 32

Holds together parts of the body, provides structure and support.

Question 33

Why is **histology** important in medicine?

Answer 33

It helps identify normal and abnormal tissues, determine disease progression, and inform treatment strategies.

Question 34

What does the **central nervous system (CNS)** consist of, and what is its protective fluid called?

Answer 34

The CNS consists of the brain and spinal cord, protected by cerebrospinal fluid.

Question 35

How do meristematic and permanent tissues differ in plants?

Answer 35

* **Meristematic tissues** are involved in growth and division. * **Permanent tissues** are specialized for functions like photosynthesis and support.

Question 36

Define an **organ**.

Answer 36

A collection of tissues that complete a function inside of an organism. ## Footnote E.g. the heart, lungs & brain

Question 37

How many organ systems are there in the human body?

Answer 37

11

Question 38

Why are organ systems important for homeostasis?

Answer 38

They maintain homeostasis by performing complex functions such as gas exchange, nutrient absorption, and waste removal.

Question 39

What are the **main levels** of biological organization from smallest to largest?

Answer 39

1. Atom 2. Molecule 3. Macromolecule 4. Cell 5. Tissue 6. Organ 7. Organ system 8. Organism 9. Population 10. Community 11. Ecosystem 12. Biosphere

Question 40

Define an **organism**.

Answer 40

A single entity of life that can reproduce, such as a plant, animal, or bacterium.

Question 41

Scientists have organized life into levels of biological organization. What is the **smallest unit**?

Answer 41

The atom.