Biology Chapter: Cell Structure and Function

Cell Structure and Function

• All living things are composed of cells, which are considered the fundamental unit of life.
• Cells can exist independently, like a single blood cell, or as part of a larger structure such as tissues and organs.
• Single celled organisms are called unicellular, such as bacteria, while organisms made up of multiple cells are called multicellular, such as animals and plants.

Reproduction

• All living organisms have the ability to reproduce, creating more of their own kind.
• Reproduction is essential for the continued existence of a species.

Growth and Development

• All living things increase in size and undergo changes over time, a process known as development.
• All organisms start as a single cell.
• Unicellular organisms like bacteria grow and develop organelles for specific functions.
• Multicellular organisms develop from a single cell that multiplies and differentiates, resulting in specialized cells with distinct functions.

Cell Differentiation

• Plants: Cells differentiate into different types, such as those for transporting water, absorbing water, and absorbing light.
• Animals: A single stem cell can replicate itself or differentiate into various cell types.

Characteristics of Life

• Cellular organization: All living things are composed of cells.
• Reproduction: All living things create more of their own kind.
• Metabolism/Requires Energy: Organisms use chemical reactions to obtain and utilize energy for life processes.
• Homeostasis: Maintaining a stable internal environment; organisms respond to changes in their surroundings and adjust accordingly.
• Heredity: Traits are passed from parents to offspring through genes, the basic units of heredity.
• Responsiveness: All living things react to stimuli.
• Growth and Development: Organisms increase in size and undergo changes over time.
• Adaptations: Inherited characteristics that help organisms survive and reproduce successfully.

Viruses: Not Living Organisms

• Viruses lack certain characteristics of life, making them non-living.
• They cannot reproduce independently and require a host cell to multiply.
• They are not made up of cells and lack the ability to grow and metabolize.

Homeostasis Explained

• Homeostasis ensures the body maintains a stable internal environment essential for proper functioning.
• Examples include regulating blood glucose levels, removing waste products, and maintaining body temperature.

What is Biology?

• The study of life.
• From the Greek words "bio" (life) and "logos" (study of).

Living or Nonliving

• Biotic Factors: Living organisms like bacteria, fungi, plants, protists, and animals.
• Abiotic Factors: Non-living things like water, soil, viruses, sun, rocks, and clouds.

Heredity

• All living organisms pass on traits to their offspring through genes encoded in DNA.

Responsiveness Examples

• Phototropism: growth of plants towards light.
• Phototaxis: movement of organisms towards or away from light.
• Thigmotaxis: response to contact or touch.
• Reflexes: protective responses in animals to avoid harm.

Adaptations: Inherited Changes

• Adaptations are inherited changes that occur over time, helping species survive and pass on their genes.

Eye Adaptation

• Different animals have different pupil shapes, influencing their vision and hunting strategies.

Behavioral Adaptations

• How an animal acts, categorized as:

  Inherited Behaviors

  • Migration
  • Hibernation
  • Being nocturnal
  • Defensive behaviors
  • Mating or courtship behaviors

  Learned Behaviors

  • Finding food
  • Making a shelter
  • Communication
  • Social behavior
  • Predator avoidance

Physical Adaptations

• Physical features that evolve over time.

  Body Parts

  • Types of feet
  • Kinds of claws
  • Types of mouths and/or beaks
  • Kinds of body coverings

  Color and Pattern

  • Camouflage
  • Mimicry