BIOLOGY COMBINED

• n 1838 Matthias Schleiden a botanist and Theodor Swann a zoologist proposed that all plants and animals were composed of cells. They proposed that cells were the basic building blocks of life.I in 1855 Rudolf Virchow stated that the chemical reactions of life took place inside cells and that new cells could only arise from thedivision of pre-existing cells
• Cell theory Cells are the fundamental units of life 2. All living organisms are composed of cells 3. All cells come from pre-existing cells4. Modern cells evolved from a common ancestor Cell contain water and molecules which the cell uses to transformmatter and energy respond to the environment and reproduce Cells are tiny. Hooke estimated that there in 1 square inch of cork there were 1 259 712 000 cells! Most cells are between 1-100 micrometers in diameter (μm)
• Cell size limited by the surface area-to-volume ratio.As an object grown larger its volume increases faster than it’s surface area
• Surface area to volume The volume of a cell determines how much chemical activity it can carry out per unit of time. The surface area of the cell determines the amount of a substance it can take in from the external environment and how much waste it can release into the environment. As a living cell grows larger its chemical activities and thus its need for resources and its rate of waste production increase faster than its surface area. Movement of substances within the cell is more easilyaccomplished in smaller cells
• For life to evolve several elements wereessential: • Nucleic acids that reproduce themselves and serve as templates for protein synthesis .• Enclosure of biological molecules by membranes made of fatty acids.
• The two main groups of prokaryotes emerged early: Bacteria and Archaea. Some early prokaryotes eventually merged to form the Eukaryotic cells thathave membrane-enclosed organelles.Some began living as colonies; some cells specialized for different functions leading to multicellular organisms.
• About 2.5 billion years ago the first photosynthetic bacteria arose. what is photosynthesis Photosynthesis transforms sunlight energy into chemical energy and is thebasis of most of life on Earth; it provides food for other organisms.Abundant O2 opened up new avenues of evolution → Aerobic metabolism is more efficient than anaerobic metabolism. Most organisms today use aerobic metabolism.
• Prokaryotic cells All prokaryotic organisms are unicellular. Do not have a nuclear membrane (i.e. circular genetic material isdispersed in cytoplasm) Have no membrane-bound organelles.Relatively small (0.1–5.0 μm in diameter)
• what is Flagella and pili? Pili = threadlike structures which help the bacteria to adhere to one anotherduring exchange of genetic material and to animal cells for protection or food. Flagella = locomotory structures shaped like corkscrews
• Examples of prokaryotic cells E.coli Pyrolobus Fumarri Methanogens
• where is the nucleolous located? In the nucleus under the endoplasmic recticulum (ER) made up of fibers joining part of the chromotin.
• can there be more than one nucleolous? yes depending on the organism
• what is the function of the nucleolous? 1. sythesis of ribosomal RNA 2. assembly of ribosomal subunits (translation of proteins)
• what is the size of nucleolous 1-2 micrometer diameter
• What is nucleus' function - contains most of the cell's genetic material as DNA - regulates all the activities of the cell and produces mRNA
• nucleus structure? surrounded by a double nuclear envelope and encloses the genetic material (chromatin)
• the size of the nucleus 5 micrometer diameter
• is the nucleus the largest organelle in the cell? yes as it is 5 micrometers
• ribosomes are located suspended in cytoplasm or bound to rough ER endoplasmic reticulum
• what subunits are ribosomes composed of? two a larger and smaller one. - messenger RNA transfer RNA and ribosomal RNA are the main
• what are the functions of the ribosomes? what size? site of protein synthesis size is 20nm unit is svedburg unit S. like how the two submits are small 40S large 60S
• what are the components of the endomembrane system? 1. Nuclear Envelope 2. Endoplasmic reticulum 3. Golgi apparatus 4. lysosomes 5. vacoules 6. plasma membrane
• What are transfer vesicles? An intracellular vesicle that carries proteins from one organelle to another. Usually goes to golgi appartus. The components of the endomembrane system are either continous or connected via transfer vesicles
• Rough Endoplasmic Reticulum (ER) location structure Located: in the cytoplasm as part of the endomembrane system Structure: A complex system of membranous tubules studded with ribosomes. Connected to the smooth ER but structurally and functionally distinct from it.
• What is the Rough ER function? - receives newly synthesized proteins and transports them to other parts of the cell. - proteins can be chemically modified and 'tagged' - proteins shipped to other parts in vesicles - produces membrane-bound proteins
• What is? A complex system of membranous tubules studded with ribosomes. Rough ER
• Golgi Appartus location and structure Located in the cytoplasm and is associated with the ER The structure is a system of flattened membranous sacs called cisternae
• what is cisternae? a system of flattened membranous sacs in the golgi apparatus
• what are the functions of the Golgi Apparatus 1. Recieves protein containing vesicles from ER 2. modifies concentrates packages and sorts protein before sending them to their cellular or extra cellular locations 3. adds carbohydrates to proteins and modifies carbohydrates that were attached to the ER 4. manufacture of some certain macromolecules such as hyaluronic acid. size: 1 micrometer
• what component of the endomembrane system modifies concentrates packages and sorts protein b4 sending them to their cellular oe extra-cellular locations? golgi apparatus
• Cytoskeleton Location and structure. Located Throughout the cell Structure: long fiborous proteins such as Microfilaments intermediate filaments and microtubules)
• Microfilaments intermediate filaments and microtubules are all examples of Long fiborous proteins or cytoskeletom
• Function of the Cytoskeleton - Provides support to the cell and maintain shape - Aid transport of vesicles and materials throughout the cell - Hold organelles in place. - Aids in cell-cell adhesion
• Different type of fibres of cytoskeleton Microfilaments: 7nm (smallest) - made of strands of protein (actin) often interacts with strands of other proteins Intermediate filaments: 8-12nm (toughest) - made up of fiborous proteins organized into tough ropelike assemlages that stabilize a cell's structure and help maintain its shape Microtubules: 25nm (largest) - long hollow cylinders made up of many molecules of protein tubulin. two sub units of tubulin: alpha tubulin and beta tubilin
• Microfilaments size: 7nm Structure: linked monomers of protein called actin and combined in a structure that resembles actin filaments. can assemble/disassemble quickly. Located bellow the cell membrane function: serves as track for the movement of a motor protein called myosin (like muscle contractions) it is important for the function of muscle cells.
• Intermediary filaments Size: 8-11 nm Structure: multiple strands of fibrous proteins wound together (ex keratin) are permanent dont move around a lot. Location: Meshwork around the cytoplasm Function: - Maintaining shape of the cell - specialized to bear tension Annchoring nucleus and other organelles in place.
• microtubules diameter: 25nm Structure: tubulin proteins arranged to form a hollow straw like tube two sub units alpha tubulin and beta tubulin. Location: typically having one end attached to a single MTOC or a microtubule organizing centre ex centrosome) function: - structural support to resist compression forces - tracks for motor proteins like kinesins and dyneins which transport vesicles. eg vesicles from ER to golgi - form the spindle during cell divison
• What is energy? Energy is the ability to do work
• first law of thermodynamics: Energy cannot be created or destroyed but can only transform from one form to another The body does not produce consume or use up energy; instead it transforms energy from one state into another as physiologic systems undergo continual change.
• does the body produces consume or use up energy? no. Instead it transforms energy from one state into another as physiologic systems undergo continual change.