assessment study 2 Flashcards
(25 cards)
theory vs law
A theory explains a wide range of phenomena supported by evidence and experimentation
e.g. Evolution, Big Bang, Cell
A law describes a specific relationship observed in nature.
e.g. Motion, Energy Conservation
what is the cell theory - 3
- Cell is the basic unit of life.
- All organisms are composed of cells.
- All cells come from pre-existing cells.
what are the organelles in a cell?
Membranes
Protoplasm
Nucleus
Endoplasmic reticulum
Golgi bodies
Ribosomes
Lysosomes
Mitochondria
Vacuoles
Chloroplasts
Plant cell wall
Centrioles
Cytoskeleton
what are prokaryotes
- No membrane bound organelles.
- Do not have any nucleus at all, so nothing protects their genetic material,
- Unicellular organisms are usually prokaryotic.
- Small, simple structures = early life forms existed
- When they clump together in nature, they are referred as colonial organisms.
what are eukaryotes
- Do have membrane-bound organelles.
- Have nucleus that protects their DNA.
- Their DNA shape is not circular like plasmids.
- Eukaryotes are much more complex than prokaryotes.
- All multicellular organisms are eukaryotic.
what is the structure of cell membrane
bilayer of phospholipids (fatty acids), that is flexible in order to change shape whenever there is a need to perform its function efficiently.
what does the cell membrane do
- protect the cell from the external environment
- control the flow of materials in and out of the cell
- maintain the turgidity of the cell.
- allows cells to communicate with each other
- Nutrients and water enter the cell. Waste products and excess water exit the cell.
proteins in the cell membrane and their function
- adhesion proteins - help cells stick to each other, maintaining tissue structure
- transport proteins - move substances across the cell membrane.
- receptor proteins - bind to specific signaling molecules, Trigger internal cellular responses
- glycoproteins - cell recognition and signaling.
whats the semi-permeable membrane
- a layer where certain molecules can pass through.
- not every chemical compound the cell is exposed to can enter a cell.
- not every component of the cytoplasm can exit the cell.
What does the “fluid mosaic model” describe.
cell membranes as dynamic structures where various components, including phospholipids, proteins, and carbohydrates, are embedded in a fluid bilayer.
whats diffusion
- the process where any materials (besides water molecules) move in and out of the cell from a high concentration to a low concentration of the same substance.
- Diffusion stops when equilibrium is reached. This means all particles of that material has been dispersed, and no more movement occurs caused by the high concentration gradient.
whats osmosis
- the diffusion of only the solvent particles, which is usually water. In osmosis, water molecules move from high concentration to low concentration.
what two proteins does passive transport rely on, and what do they do?
channel protein: these proteins form channels or in the cell membrane, allowing specific ions and small molecules to pass through.
carrier protein: these proteins bind to specific molecules on one side of the membrane, undergo a conformational (shape) change, and release the molecule on the other side.
whats passive transport
the transfer of materials across the membrane that does not require energy.
what are the types of application in passive transport
Hypertonic: Water moves out by osmosis (cell shrivels)
Hypotonic: Water moves in by osmosis (cell is full – may pop)
Isotonic: No water movement (cell is normal)
whats active transport
when molecules move from low concentration to high concentration & those that are too large to go through freely across the membrane are needed to be transported. Because of this, energy is used.
whats endocytosis
When a large particle or molecule needs to enter a cell, the cell engulfs it by forming a mouth-shape in its membrane, then brings the particle inwards. There are two types of endocytosis: pinocytosis (drinking) and phagocytosis (eating).
whats exocytosis
When the cell produces a large particle/s that is needed externally or some waste that need to remove, exocytosis occurs. This happens when a layer of the membrane is formed around the particle in the cytoplasm totally surrounding it then is driven to the surface to transport particles outward.
whats photosynthesis (biochemical process)
a biochemical process that occurs in chloroplasts in plants. The green pigment in chlorophyll absorbs light energy, which is transformed into usable energy for the plant which is glucose. See the chemical equation below.
whats respiration (biochemical process)
- a biochemical process that occurs in the mitochondria of the cell. All eukaryotes have mitochondria.
- In this organelle, the chemical compound glucose is broken down in the presence of oxygen to produce ATP the energy molecule and carbon dioxide gas is expelled as waste.
types of respiration
- Aerobic Respiration:
Energy-releasing process that requires oxygen to break down glucose into carbon dioxide, water, and ATP. - Anaerobic Respiration:
Energy-releasing process that occurs without oxygen, breaking down glucose into less energy and byproducts like lactic acid (in animals) or ethanol + CO₂ (in yeast).
Accuracy
How close your measurement is to the true or accepted value
Precision
How close your measurements are to each other when you repeat them.
Reliability
When someone and you receive the same results after repeating.
