Biology: Nutrition and Respiration

Nutrition

• Autotrophic nutrition: Plants, algae, and some bacteria make their own food through photosynthesis, using sunlight, water, and CO2.
• Heterotrophic nutrition: Animals, fungi, and some bacteria obtain energy by consuming other organisms or organic matter.

Respiration

• Aerobic respiration: Cellular respiration that occurs in the presence of oxygen (O2), producing energy (ATP) and water (H2O) as byproducts.
• Anaerobic respiration: Cellular respiration that occurs in the absence of oxygen (O2), producing energy (ATP) and lactic acid or ethanol as byproducts.

Transportation

• ** Circulatory system**: Heart, blood vessels, and blood work together to transport oxygen, nutrients, and waste products throughout the body.
• Transport mechanisms:
  • Passive transport: Diffusion, osmosis, and facilitated diffusion allow molecules to move across cell membranes without energy expenditure.
  • Active transport: Energy-dependent processes, such as carrier proteins and pumps, move molecules across cell membranes against their concentration gradient.

Excretion

• Excretory organs: Kidneys, liver, lungs, and skin remove waste products from the body.
• Excretory processes:
  • Filtration: Waste products are filtered from the blood by the kidneys.
  • Reabsorption: Essential nutrients and water are reabsorbed into the bloodstream.
  • Secretion: Waste products are secreted into the urine.

Coordination

• Nervous system: Central nervous system (brain and spinal cord) and peripheral nervous system (nerves) work together to coordinate body functions.
• Hormonal control: Endocrine glands produce hormones that regulate various physiological processes, such as growth and development.

Reproduction

• Asexual reproduction: Single parent produces genetically identical offspring, e.g., binary fission in bacteria.
• Sexual reproduction: Two parents produce genetically unique offspring, e.g., meiosis in animals and plants.

Nutrition

• Plants, algae, and some bacteria make their own food through photosynthesis, using sunlight, water, and CO2.
• Animals, fungi, and some bacteria obtain energy by consuming other organisms or organic matter.

Respiration

• Aerobic respiration occurs in the presence of oxygen (O2), producing energy (ATP) and water (H2O) as byproducts.
• Anaerobic respiration occurs in the absence of oxygen (O2), producing energy (ATP) and lactic acid or ethanol as byproducts.

Transportation

• The heart, blood vessels, and blood work together to transport oxygen, nutrients, and waste products throughout the body.
• Diffusion, osmosis, and facilitated diffusion allow molecules to move across cell membranes without energy expenditure.
• Carrier proteins and pumps move molecules across cell membranes against their concentration gradient, requiring energy.

Excretion

• The kidneys, liver, lungs, and skin remove waste products from the body.
• Filtration removes waste products from the blood by the kidneys.
• Reabsorption reabsorbs essential nutrients and water into the bloodstream.
• Secretion secretes waste products into the urine.

Coordination

• The central nervous system (brain and spinal cord) and peripheral nervous system (nerves) work together to coordinate body functions.
• Endocrine glands produce hormones that regulate various physiological processes, such as growth and development.

Reproduction

• Asexual reproduction produces genetically identical offspring, e.g., binary fission in bacteria.
• Sexual reproduction produces genetically unique offspring, e.g., meiosis in animals and plants.