Module 2 Flashcards
(55 cards)
Plasma Membrane
A lipid bilayer which forms the external boundary of a cytoplasm of a cell
Function of Plasma Membrane
- Isolation
- Controlling entry and exit of materials
- Sensitivity to the Environment
- Support
Plasma Membrane’s Structural Features
- Membrane Lipids
- Membrane Proteins
- Membrane Carbohydrates
Membrane Lipids
Lipids form a double-layered surface the plasma membrane
Membrane Proteins
A protein molecule that is attached to, or associated with, the membrane of a cell
Membrane Proteins: Integral
Cannot be easily operated from plasma membrane without damaging or destroying it
Membrane Proteins: Peripheral
Bound to the inner/outer surface of the membrane and are easily separated from it
Membrane Carbohydrates: Lubrication and Protection
The glycoproteins and glycolipids from a thick and sticky layer that lubricates and protects the plasma membrane
Membrane Carbohydrates: Anchoring and Locomotion
Due to it’s components being sticky, the glycocalyx can help anchor the cell in place
Membrane Carbohydrates: Specificity in Binding
Glycoproteins and glycolipids can function as receptors, binding specific extracellular compounds
Membrane Carbohydrates: Recognition
Cells involved with the immune response recognise glycoproteins and glycolipids as normal or abnormal.
The body recognises it’s own glycoproteins and glycolipids as “self” rather than “foreign”.
Organelles of a Cell
- Non-membranous Organelles
- Organelles (“little organs”)
- Cytoskeleton
- Microvilli
Organelles of a Cell: Non-membranous Organelles
Not completely enclosed by membranes and do not have a definite boundary
Organelles of a Cell: Membranous
Isolated from the cytosol by phospholipid membranes, just as the plasma membrane isolates the cytosol from the extracellular fluid
Organelles of a Cell: Organelles (“little organs”)
Internal structures of cells that perform most of the tasks that keep a cell alive and functioning
Organelles of a Cell: Cytoskeleton
Serves as the cell’s skeleton — an internal protein framework that gives the cytosol strength and flexibility
Organelles of a Cell: Microvilli
Small, finger-like membrane protrusions of the plasma membrane that increase the surface area exposed to the extracellular environment
Nucleus
- The largest and most visible structure in a cell
- Contains a supportive nuclear matrix
Genetic Coding
A triplet code - a sequence of three nitrogenous bases specifies the identity/translates into a single amino acid = building blocks of proteins
Proteins Synthesis
The process where biological cells generate new proteins from amino acid “building blocks” — balanced by the loss of cellular proteins via degradation/export
Transcription
The transfer of genetic instructions in DNA to mRNA from the nucleus to the cytoplasm, which is used as a template for the instructions to make protein
The process by which DNA is copied to RNA is called transcription
Translation
The instructions in mRNA are read, and tRNA brings the correct sequence of amino acids to the ribosome
RNA is used to produce proteins is called translation
Cell Structure
Semi-permeable membrane, a nucleus and cytoplasm
Cellular/facilitated Diffusion
Molecules move across the plasma membrane from an area where they are at a higher concentration to areas where they are at a lower concentration until equilibrium is reached
