Cell Structure Overview

Cell Structure

• Cells are the basic building blocks of all living organisms.
• Different cell structures have specialized functions.
• Plant and animal cells share some structures but have unique organelles.
• Common structures include cell membrane, cytoplasm, nucleus, mitochondria, ribosomes, and endoplasmic reticulum.
• Plant cells possess chloroplasts and a cell wall, unlike animal cells.
• Cell membranes regulate substance passage into and out of the cell.
• Cytoplasm is the jelly-like substance filling the cell.
• The nucleus controls cellular activities and holds genetic material.
• Mitochondria are sites of aerobic respiration, producing cellular energy.
• Ribosomes synthesize proteins.
• Endoplasmic reticulum facilitates material transport within the cell.
• Chloroplasts are the sites of photosynthesis in plant cells, converting light energy to chemical energy.
• Cell walls provide structural support and protection to plant cells.

Cell Organisation

• Cells form tissues.
• Tissues combine to create organs.
• Organs work together in organ systems.
• Examples include the nervous system and digestive system.
• Organisms function due to intricate interactions between cells, tissues, organs, and organ systems.

Movement in and out of cells

• Substances move across cell membranes through diffusion, osmosis, and active transport.
• Diffusion moves particles from high to low concentration.
• Osmosis moves water across a selectively permeable membrane from high to low water potential.
• Active transport moves substances against their concentration gradient, requiring energy.
• These processes are crucial in maintaining a stable internal environment (homeostasis).

Biological Molecules

• Living organisms are composed of complex molecules.
• Carbohydrates (starch, glucose, glycogen) provide energy.
• Lipids (fats and oils) are energy sources and constituents of cell membranes.
• Proteins perform numerous cellular functions, including acting as enzymes (catalysts).
• Nucleic acids (DNA and RNA) store and transmit genetic information.
• Diverse molecules have diverse functions in the body.

Enzymes

• Enzymes are biological catalysts, speeding up chemical reactions in living organisms.
• Enzymes are specific to their substrates (the substance they act upon).
• Temperature, pH, and substrate concentration affect enzyme activity.
• Enzyme activity is essential to metabolic processes.

Photosynthesis

• Photosynthesis is the process where plants convert light energy into chemical energy.
• It occurs within chloroplasts and involves converting carbon dioxide and water into glucose, releasing oxygen.
• The equation for photosynthesis is 6CO2 + 6H2O → C6H12O6 + 6O2 (carbon dioxide + water → glucose + oxygen).
• Photosynthesis provides oxygen, crucial for life.

Respiration

• Respiration is the process of releasing energy from glucose.
• Respiration can be aerobic (requiring oxygen) or anaerobic (without oxygen).
• Aerobic respiration releases more energy than anaerobic respiration.
• The equation for aerobic respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen → carbon dioxide + water).
• Anaerobic respiration produces fewer energy molecules and byproducts like lactic acid in animals.

Biological Membranes

• Cell and organelle membranes are selectively permeable, controlling substance movement.
• Membrane structure and properties determine what substances can pass through.
• Membrane transport is critical for cellular function and homeostasis.

Transport in Plants

• Plants transport water, mineral ions, and sugars via specialized systems.
• Xylem vessels transport water and mineral ions from roots to leaves.
• Phloem vessels transport sugars from leaves to other plant parts.
• Understanding plant transport systems unveils insights into plant physiology and nutrition.

Excretion

• Plants and animals remove waste products to maintain a stable internal environment (homeostasis).
• Different animals exhibit different excretory systems.

Homeostasis

• Homeostasis maintains a stable internal environment in an organism.
• Factors like temperature, water content, and blood glucose levels are regulated for optimal function.
• Feedback mechanisms ensure the stable internal environment is maintained.

Human Digestive System

• The human digestive system breaks down and absorbs food.
• Physical and chemical digestion breaks food into absorbable molecules.
• The digestive system includes organs like the mouth, esophagus, stomach, small intestine, and large intestine.
• Enzymes aid chemical digestion.
• Nutrient absorption occurs in the small intestine.

Human Respiratory System

• The human respiratory system facilitates gas exchange (taking in oxygen, releasing carbon dioxide).
• Key organs include lungs and trachea.
• Breathing involves inspiration (inhaling) and expiration (exhaling).
• Efficient gas exchange is crucial for cellular respiration.

Human Nervous System

• The human nervous system coordinates body functions, comprising central (brain and spinal cord) and peripheral components.
• Neurons transmit signals.
• Sensory and motor neurons respond to and act on stimuli.
• Processes like reflexes and behaviors are governed by the nervous system.

Reproduction

• Reproduction creates new organisms.
• Sexual and asexual reproduction differ.
• Sexual reproduction involves fusion of male and female gametes.
• Asexual reproduction involves a single parent.
• Understanding reproduction is important for population dynamics and conservation.

Explore the fascinating world of cell structures in this quiz. Understand the functions of various organelles in both plant and animal cells, including their unique characteristics. Test your knowledge on the building blocks of life and their roles in organisms.