Biology Pointers

• Biology


  The study of living organisms/things
• Fields of study in the biological sciences

  • Zoology: The study of animal life
  • Botany: The study of plant life
  • Ecology: The study of the relationship of living things to their environment
  • Embryology: The study of the formation and development of organisms in their earliest stages of life
  • Anatomy: The study of structures of the body
  • Physiology: The study of the functions of the body
  • Genetics: The study of heredity
  • Cytology: The study of the cell
  • Histology: The study of tissues
  • Bacteriology: The study of bacteria and/or unicellular plant life
• Biology includes biological concepts and process skills, technology and attitudes and values for addressing the needs and problems of society
• In recent years, the development of techniques in genetic engineering and increased understanding of the molecular basis of cellular processes have led to the emergence of a new and exciting field of scientific research called biotechnology
• Cell


  The basic structure of all living things
• Most cells can reproduce to form new cells which are almost identical to the original cell
• Types of cell reproduction

  • Sex cells reproduce by meiosis
  • Somatic cells (autosomes or body cells) reproduce by mitosis
• Prokaryotic cells


  Cells that do not have a nuclear membrane or membrane-bound organelles
• Eukaryotic cells


  Most cells making up all other living organisms
• Cell membrane


  A double layer of lipids that surrounds the cell, thus acting as a "gatekeeper," controlling what moves into and out of the cell
• Components of a generalized cell

  • Nucleus
  • Cytoplasm
• Organelles that a cell can contain

  • Mitochondria
  • Chloroplast
  • Plastids
  • Lysosomes
  • Smooth Endoplasmic Reticulum
  • Rough Endoplasmic Reticulum
  • Golgi Apparatus
  • Peroxisomes
  • Vacuoles
  • Basal bodies
  • Cell wall
  • Centrioles
  • Nucleolus
  • Chromosomes
  • Ribosome
• Plant cells have most of the same structure as animal cells except for centrioles
• Plant cytoplasm also contains vessels called chloroplasts that capture light energy and use it to make the cell's food
• Plant cells also have a tough cell wall surrounding the cell membrane; the cell wall gives a plant its stiffness
• Not every cell expresses all the genetic information, as cells develop in different ways as the embryo develops
• Homeostasis


  The balance or working equilibrium that is optimum for the cell's needs
• Ways materials move into and out of the cell

  • Active transport
  • Passive transport
  • Endocytosis
  • Phagocytosis
  • Exocytosis
• Turgor pressure is necessary for the cell to adjust to its needs and environment
• Proteins are used by the cell or organism to provide energy, general maintenance, growth, and reproductive functions
• Protein degradation


  1. Proteins are broken down into amino acids

  2. Amino acids are reconstructed into peptide chains (by the process of protein synthesis)
• Mitosis


  A form of cell division whereby each of two daughter nuclei receives the same chromosome complement as the parent nucleus
• Stages of mitosis


  1. Interphase

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase
• Meiosis


  Two successive cell divisions where chromosomes duplicate only once, resulting in daughter cells with a haploid number of chromosomes
• Basic functions of life

  • Respiration
  • Assimilation
  • Regulation
  • Synthesis
  • Irritability
  • Movement
  • Bioluminescence
  • Transportation
  • Metabolism
  • Ingestion
  • Digestion
  • Secretion
  • Absorption
  • Excretion
  • Reproduction
• Types of reproduction


  • Asexual: Fission, Budding, Sporulation
  • Sexual: External Fertilization, Internal Fertilization
• Photosynthesis


  A process that occurs within all plant cells which supply all of the carbohydrates used by both plants and animals
• Fertilization


  The union of sperm cells and egg cells
• Types of fertilization


  • External fertilization
  • Internal fertilization
• External fertilization


  The union of sperm cells outside the body of the female organisms
• External fertilization


  • seashells, starfishes, frogs, fishes
• Internal fertilization


  The union of sperm cells and egg cells inside the body of a female organism
• Internal fertilization


  • higher forms of animals and humans
• Photosynthesis


  1. Chloroplasts absorb light energy

  2. Carbon dioxide and water are present as raw materials

  3. Light energy is converted to chemical energy in the form of ATP and NADPH

  4. ATP and NADPH participate in the formation of sugar
• Photosynthesis is a two-step process involving light reactions and dark reactions
• Sugar, particularly glucose, is the starting material for the production of other food molecules such as more complex carbohydrates, proteins, and fats
• The food of land organisms come from green plants while aquatic organisms feed on chlorophyll-bearing algae and plankton
• Aside from producing food and oxygen, photosynthesis helps to keep a constant level of carbon dioxide in the atmosphere
• Cellular respiration


  1. Carbohydrates, fats, and proteins are broken down to produce energy in the form of ATP

  2. Oxygen is consumed and carbon dioxide and water are produced as by-products
• In eukaryotic cells, cellular respiration takes place in the mitochondria. In prokaryotic cells, like bacteria, this process takes place on the cell membrane since bacteria do not contain mitochondria