Science

• Life processes are the processes that all living organisms carry out to maintain life
• Living organisms are called organisms, including both plants and animals
• The distinction between living and non-living things is based on the 7 life processes that living things carry out
• Movement:

  • Both animals and plants have the ability to move
  • Plants move slowly as they grow, with roots moving down into the soil and stems moving up towards the light
  • Animals can move their entire bodies quickly in search of food, shelter, or to avoid danger
• Respiration:

  • Respiration is the process of extracting energy from food
  • All living things respire to grow, replace worn out parts, and move
  • Respiration takes place in the mitochondria of the cell
• Sensitivity:

  • Living organisms are sensitive and have an awareness of changes in their environment
  • Animals respond quickly to stimuli like heat, light, sound, touch, and chemicals
  • Plants are generally less sensitive and have slower responses
• Growth:

  • All living organisms grow
  • Plants continue growing throughout their lives, while animals stop growing once they reach adulthood
  • Even when growth stops, materials within an animal's body are still being replaced from its food
• Excretion:

  • All living things produce waste products that need to be eliminated
  • Excretion is the process of getting rid of metabolic waste
  • Plants store waste substances in their leaves and remove them when leaves fall off, while animals excrete waste through urine, sweat, and breathing out carbon dioxide
• Reproduction:

  • All living things must produce offspring for their species to survive
  • Reproduction can be sexual, involving two parents and the union of gametes, or asexual, where one parent can reproduce itself
  • Plants produce seeds for new plants, while animals lay eggs or have babies
• Nutrition:

  • Nutrition is needed for energy and growth
  • Plants make their own food through photosynthesis using sunlight, carbon dioxide, and water
  • Animals rely on other plants and animals for nutrition, taking in complex substances and breaking them down into simple molecules for energy and growth
• Autotrophic Nutrition:

  • Autotrophs can prepare their own food from simple inorganic sources like carbon dioxide and water
  • Examples include green plants and some bacteria
• Heterotrophic Nutrition:

  • Heterotrophs cannot synthesize their own food and depend on other organisms for obtaining complex organic substances
  • Examples include animals and fungi
• Holozoic Nutrition:

  • Complex food is taken into a specialist digestive system and broken down into small pieces to be absorbed
  • Examples include Amoeba and Humans
• Saprophytic Nutrition:

  • Organisms feed on dead organic remains of other organisms
  • Examples include fungi like bread molds, yeast, and mushrooms
• Parasitic Nutrition:

  • Organisms obtain food from other living organisms without benefiting the host
  • Examples include cascuta, ticks, lice, leeches, and tapeworms
• Transportation in Human Beings:

  • The circulatory system composed of the heart, blood, and blood vessels transports materials throughout the body
  • The heart has four chambers, two atria, and two ventricles, preventing mixing of oxygen-rich and carbon dioxide-rich blood
  • Arteries carry blood from the heart, veins deliver blood back to the heart, and capillaries exchange materials between blood and cells
• Excretion in Human Beings:

  • The excretory system in humans includes kidneys, ureters, urinary bladder, and urethra
  • Kidneys filter waste products and excess substances from the blood to produce urine
  • Urine is stored in the bladder and excreted through the urethra
• Transportation in Plants:

  • Xylem moves water and minerals from roots, while phloem transports products of photosynthesis
  • Transpiration helps in the absorption and upward movement of water and minerals in plants
  • Phloem translocates food and substances using energy from ATP
• Nervous system comprises of the brain, the spinal cord, and a huge network of nerves spread throughout the body
• Nervous tissue is made up of an organized network of nerve cells or neurons
• A neuron consists of three parts: the cell body or cyton, branched projections called dendrites, and the long process from the cell body called the axon
• Synapse is a gap between two neurons
• Types of nerve cells or neurons:

  • Sensory nerves send messages from sense organs to the brain or spinal cord
  • Motor nerves carry messages back from the brain or spinal cord to all muscles and glands in the body
  • Interneuron or relay neuron connects neurons within specific regions of the central nervous system
• Reflex action is an involuntary and nearly instantaneous movement in response to a stimulus
• Central nervous system includes the brain and the spinal cord
• Brain has three major parts: forebrain, midbrain, and hindbrain

  • Forebrain consists of the cerebrum and diencephalon
  • Midbrain connects the forebrain to the hindbrain and controls reflexes for sight and hearing
  • Hindbrain consists of the cerebellum, pons, and medulla
• Peripheral nervous system consists of cranial and spinal nerves arising from the brain and spinal cord respectively
• Human brain is protected by the thick bones of the skull and a fluid called cerebrospinal fluid for shock absorption
• Muscle cells move by changing their shape so that they shorten in response to nervous electrical impulses
• Plants respond to stimuli with the help of chemical compounds secreted by cells and exhibit movements
• Plants show two types of movement: one dependent on growth and the other independent of growth
• Different plant hormones help coordinate growth, development, and responses to the environment

  • Auxins help in growth by cell elongation and induce shoot apical dominance
  • Gibberellins help in stem growth, seed germination, bolting, and flowering
  • Cytokinins are present in areas of rapid cell division and promote stomata opening
  • Abscisic acid inhibits growth in various parts and is responsible for the closure of stomata
• Endocrine system is formed by ductless glands which secrete hormones directly into the blood
• Different types of endocrine glands in the body include the pituitary gland, pineal gland, hypothalamus, thyroid, parathyroid, thymus, adrenal gland, pancreas, testes, and ovary
• Adrenal glands are located above the kidneys and have two regions: adrenal cortex and adrenal medulla

  • Adrenal cortex secretes hormones like cortisol, aldosterone, and androgens
  • Adrenal medulla secretes hormones like adrenaline and noradrenaline
• Thyroid gland is located in the neck and produces hormones like triiodothyronine and thyroxine

  • Thyroxine regulates metabolism of carbohydrates, proteins, and fats in the body
  • Iodine is essential for the synthesis of thyroxin
• Pituitary gland is located at the base of the brain and secretes hormones to regulate organs and other glands

  • Different hormones secreted by the pituitary gland include Growth hormone, TSH, FSH, LH, ACTH, MSH, Vasopressin, and Oxytocin
• Female gonads are ovaries that produce hormones like oestrogen and progesterone

  • Oestrogen controls changes during puberty
  • Progesterone controls uterine changes in the menstrual cycle and helps in the maintenance of pregnancy
• Male gonads are testes that produce the hormone testosterone

  • Testosterone controls changes during puberty
• Pancreas is both exocrine and endocrine in function

  • It secretes hormones like insulin, glucagon, somatostatin, and pancreatic polypeptide
  • Insulin regulates sugar levels in the blood