Lecture 4 - Plasma Membrane And Organelles Flashcards
What does a cell do?
- Manufacture cellular materials
- Obtain raw materials
- Remove waste
- Generate the required energy
What does an animal cell have that a plant cell doesn’t and vice versa?
Animal cells have lysosomes
Plant cells have a central vacuole and chloroplasts
What is the nucleus in a cell?
The nucleus is a membrane bound organelle that contains DNA of eukaryotic organisms. It facilitates transcription and replication processes
What is the endoplasmic reticulum? (ER)
The endoplasmic reticulum is a network of tubules and flattened sacs that perform multiple functions in both plant and animal cells
What is smooth and rough ER in a cell?
Smooth ER doesn’t contain ribosomes and serves a transitional area for transport vesicles. It also functions in carbohydrate and lipid synthesis.
Rough ER contains ribosomes and synthesizes proteins via the translation process. It also manufactures membranes
What is the Golgi apparatus in a cell?
The Golgi apparatus is a cell organelle that helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell. The Golgi body appears as a stacked membrane
Organelles have varying functions and most of them are surrounded by membranes, creating separate environments. List 5 things that organelles do :
- Provide special conditions for specific processes
- Keep incompatible processes apart
- Allow specific substances to be concentrated
- Form concentration gradients
- Package substances for transport or export
What is the purpose of a phospholipid bilayer?
Phospholipid bilateral create a selectively permeable barrier to the movement of ions and molecules important for cellular function. They make up the basic fabric of the plasma membrane
What is endocytosis?
Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane
What is the difference between a hydrophilic head and a hydrophobic tail in the phospholipid bilayer?
Hydrophilic head = attracted to water
Hydrophobic tail = repelled by water
What is unsaturated verses saturated hydrocarbon tails?
Fluid - unsaturated tails prevent packing
Viscous - saturated tails pack together
What are the four types of movement across the membrane?
- Passive transport - diffusion
- Passive transport - facilitated diffusion
- Active transport
- Co transport
Define active transport?
The movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy
Define Co-Transport?
The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient
- transported alongside something else
