Cells as the Basis of Life Flashcards
Nucleus: structure and function
Membrane bound, contains DNA
Contain genetic instructions for cell growth, repair and functioning
Nucleolus: structure and function
Made of protons and RNA (in the nucleus)
Makes ribosomes
Ribosomes: structure and function
Made of protein and RNA
Make proteins
Endoplasmic Reticulum: structure and function
Network of flat, interconnected membranes
Rough ER: HAS ribosomes
Smooth ER: NO ribosomes
Rough ER: processes and modify proteins
Smooth ER: make lipids
Golgi body
Flat, membrane-bound sacs that aren’t connected to each other
Processes and packages substances made in the cell, e.g: proteins
Lysosomes
Membrane-bound vesicle that contains digestive enzymes
Breaks down cellular waste and forge in particles
Cell definition
A cell refers to the smallest structural and functional unit of a living organism
Organelles definiton
Membrane-bound coparents within the cell (have their own function)
Chloroplasts: Function and structure
Disk-shaped with a double membrane, DNA and chlorophyll
Use light energy, carbon dioxide and water to produce glucose via photosynthesis
Mitochondria: Function and structure
Have a double membrane (inner membrane highly folded) and DNA
Use oxygen and glucose to produce ATP (via respiration)
Cell membrane: Function and structure
Flexible, semi-permeable membrane
Protect/contain organelles and control movement of substances in/out oil cell
Cell wall: Function and structure
External structure which surrounds cell membrane (composition varies)
Structural strength and protection)
Cytoplasm: Function and structure
Watery, gel-like fluid
Suspends organelles, give the cell shape
Centrioles: Function and structure
A pair of small, cylindrical structures made of microtubules
Movement
Vacuole: Function and structure
Membrane-bound, fluid-filled vesicle
Store substances; turgor pressure maintains shape/structure in plants
The Fluid Mosaic model structure and fucntion
Cell membranes are phospholipid bilayers = 2 layers of phospholipid molecules (hydrophilic phosphate head and 2 hydrophobic lipid tails). Scattered through are carbohydrates, cholesterol and proteins
Main function of the cell membrane:
- Seperate the cytoplasm from the external environment (all cells) and create organelles (only eukaryotes)
- Regulate the movement of substances
- Communicate and recognise
Prokaryotes and Eukaryotes
Prokaryotic DOES NOT have a nucleus and membrane-bound organelles
Eukaryotic HAS a nucleus and membrane-bound organelles
Rules for biological drawing
Materials Positioning Size Accuracy Labels Title Scale
Light Microscope
- A light microscope uses light and 2 lenses( ocular and objective) to make the specimen look bigger
- It works by passing light through the specimen; this light is then reflected
- A specimen might be a: whole organism, smear of cells, thin slice of tissue
- We use staining techniques to help us see different cell structures more clearly
The confocal microscope is an example of an advanced light microscope
- It uses a laser to focus light on a very small section of the specimen
- This is used to create an image of the section
- The images produced are then stitched together to form a higher quality, 3D image
Magnification = Magnified size/ Actual size
Electron Microscope
- An electron gun shoots a beam of electrons at the specimen (in a vacuum)
- These electrons interact with the specimen and bounce everywhere
- Detectors measure the ricochet and a computer uses this information ro make an electron micrograph
Diffusion
- Passive: Movement of materials across the cell embrace WITHOUT the expenditure of energy
- Diffusion: Movement of any material from high to low concentration
- Simple: Though a phospholipid bilayer
- Facilitated: Though selective channel and carrier proteins
Osmosis
Osmosis refers to the movement of water form an area of high water concentration to an area of low water concentration across a semipermeable membrane
isotonic solutions- equal solute concentrations
A hypotonic solution- lower solute concentration
A hypertonic solution- higher collate concentration
Differences between osmosis and diffusion
Osmosis exclusively refers to movement of water across a semipermeable membrane, whilst. diffusion is the movement of any material and doesn’t have ti involve a semipermeable membrane
Active Transport
1.Movementof materials across the cell membrane that does require the expenditure of energy
2.
- Individual uses. carrier proteins to move individual molecules from low to high concentrations
- Bulk uses vesicles to move materials which are too big or when there’s too much
3.Endocytosis:move materials in cel
Exocytosis: Move materials out of cell.
Factors Affecting the Rate of Exchange
The stopper the concentration gradient, the:
- Faster the material will move towards the area of low concentration in passive transport
- Slower the material will move towards the area of high concentration in active transport (unless the cell uses more energy)
A the size of an object. decrease, its SA:V ration increases
Bigger SA:V ratio = move efficient movement of materials across the cell membrane. 2 main strategies to increase SA:V ratio:
1.Flattened shape
2. Cell membrane extensions
The smaller the particles, higher the temperature, the higher the rate of dissuasion
Cell Requirements
- All cells need ATP energy to preform the rwcatiojs they need to survive
Cells make ATP using energy from the breakdown of food
there are 2 groups of organisms based on how they get food:
1. Autotroph- Organism, which uses energy and inorganic compounds too make its own food e.g: plants, algae and some bacteria
2. Heterotroph- organisms that can’t make its own food and so it gets its nutrients by. consuming other organisms, e.g: animals, most bacteria, protists
Waste Removal
Its important to ensure waste products are removed Bec use they can interrupt normal functioning
Destroy cellular structures e.g: CO2 and nitrogenous wastes
Take up space impact osmoregulation e.g: water
Cellular level: applies to all calls
- Passive removal- carbon dioxide, alcohol, ammonia, urea and water
- Active removal- nitrogenous wastes, ions and most other toxins
Body system level- Applies to multicellular organisms:
plants- leaves release gaseous CO2 & H2O; other water via old leaves, bark and soil
Animals- ;lungs release gaseous CO2 &H20; liver processes water, kidney filters blood and removes it
Photosynthesis
Photosynthesis is the processes by which plants use sunlight to make their own organic compounds
Carbon dioxide → water → sunlight → glucose + oxygen
- Light-Dependent occur in the thylakoids
Chlorophyll captures light energy (from the sun) → light energy is used to break water down into oxygen and hydrogen - Light-Independent occur in the stream
ATP energy used ti combine carbon dioxide with hydrogen → glucose is produced
The rate of photosynthesis is affected by a combination light intensity, CO2 levels and temperature
Enzymes
Enzymes are biological catalysts
Proteins that speed up the chemical reactions occurring inside cells (without. being use dup in the process)
Enzymes are very sensitive- their activity is affected by temperature, PH and substrate concentration
Pinocytosis
takes in fluids and soultues
Phagocytosis
Takes in larger substances (bascteria)
Receptor-mediated endocytosis
absorb metabolites, hormones, proteins
Allelopathy
Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial or detrimental effects on the target organisms and the community.
Trees are great examples of allelopathy in plants. For instance, many trees use allelopathy to protect their space by using their roots to pull more water from the soil so other plants cannot thrive. … Other trees that are known to exhibit allelopathic tendencies include maple, pine, and eucalyptus
