Biology Unit Flashcards
What does the Cell Membrane do?
- Transports
- Serves as a protective barrier
- Recognition
What does the Nucleus do?
- Contains DNA
- Directs cell activity
What does the Cytoplasm do?
- Jelly-like
- Contains nutrients
What does the Cell Wall do?
PLANTS ONLY
- Rigid
- Provides strength and support
What does the Chloroplast do?
- PLANTS ONLY*
- Contains chlorophyll for photosynthesis
What does the Vacuoles/Vesicles do?
- Transports and stores nutrients
- Membrane bound
What does the ER (Endoplasmic Reticulum) do?
- Transports materials
- Rough ER ——–> with ribosome
- Smooth ER ———> no ribosome
What does the Ribosome do?
- Site of protein synthesis
- On ER (rough)
What do the Lysosomes do?
- Digestion
- Membrane bound
What does the Golgi Apparatus do?
- Receives from ER
- Packages for transport out of cell
What does the Mitochondria do?
- Cell respiration to make ATP
What is ATP (Adenosine Triphosphate)
A molecule that carries energy within cells.
What does the Centrioles do?
- Used in cell reproduction
What are cell membranes made up of?
Bilayer of phospholipids
What is the composition of the phospholipid bilayer?
Head - phosphate & glycerol (hydrophilic)
Tail - fatty acid (hydrophobic)
Why does the phospholipid bilayer form?
Since the head of a phospholipid is hydrophobic it is attracted to the water molecules in the cytoplasm and outside the cell and because the tail is hydrophobic it is repelled from the water inside and outside the cell, forming the bilayer
What role do proteins play in a membrane?
- Help transport substances across the membrane
- Cell to cell communication
How to substances enter the membrane?
- Small particles (ex. H2O, C6H12O6) can fit in-between the phospholipids
- Membrane proteins stick out of bilayer and bind to molecules to let them in
What is passive transport?
- Molecules moving across membrane
- High concentration ——–> low concentration
- No energy needed
What are the ways of passive transport?
- Diffusion
- Osmosis
- Facilitated diffusion
What is a hypotonic solution?
- A solution that contains a higher concentration of water/solvent than salt/ solute
- Hypotonic CELLS lose water
What is a hypertonic solution?
- A solution that contains a higher concentration of salt/solute than water/solvent
- Hypotonic CELLS lose water
What is an isotonic solution?
- A solution that contains an equal concentration of both water/solvent and salt/solute
- Water moves in and out at the same rate
What happens to a living cell with too much/too little water (osmosis in living cells)
- Burst (too much water)
- Shrivel (not enough water)
What does a carrier protein do?
Changes shape for the particles to allow them into the cell membrane
What does a channel protein do?
Creates a tunnel for particles to allow them into the cell membrane
What is active transport?
- Cells moving across the membrane
- Low concentration ——-> High concentration
- Energy needed (ATP)
What is endocytosis?
- Cell membrane forms a pocket for substances to be transported
- Pinches off as a vesicle which transports contents to other locations in the cell or to the vacuole for storage
What are the 3 types of endocytosis?
- Phagocytosis —–> “eating” large particles
- Pinocytosis —–> “drinking” fluid particles
- Receptors —–> proteins protruding the membrane detect and bind to specific compounds that are needed
What is exocytosis?
- The opposite of endocytosis
- Materials stored in vesicles or vacuoles (waste) are released and exit the cell
How does cell size correlate with diffusion?
Cell size determines the SA/V ratio which also affects diffusion rates
Why does the SA/V ratio affect diffusion rates?
The more surface area, the more access cells have to leave the membrane, but when a cell’s size increases, the volume increases faster than the SA. This means there is more substance, but less surface area for it to leave, leading to a less efficient diffusion rate.
What is a Multicellular Organism?
An organism that consists of more than one cell
Define: Organelles
Organelles within a cell perform the specialized functions
Define: Cell
Cells are the basic unit of organization in an organism (smallest functional unit of life)
Define: Tissue
Tissue is a cluster of cells similar in structure and function
Define: Organ
Organ if a group of tissues working together to perform a specialized function
Define: System
Systems are made up if multiple organs functioning together at a high level of organization
What is the root system? What does it do and where is it found?
The root system of a plant is below the ground and its main functions are to take in oxygen, water and nutrients from the soil, to move them up through the plant and to store a reserve of foods.
What is the shoot system? What does it do and where is it found?
The shoot system of a plant is found above the ground where it absorbs the light needed for photosynthesis and consists of stems, leaves, and the reproductive parts of the plant.