Central Dogma and Plasma Membrane Organisation and Function Flashcards
Name the two (2) cellular processes involved in gene expression in the order they occur.
Transcription
Translation
Define each of these Transcription and Translation
Transcription: (means copy) The information in a specific region of DNA is copied to produce a specific molecule of RNA.
Translation: The RNA attaches to a ribosome where the information in the RNA is translated into amino acids to form a new protein.
List the three (3) steps in Transcription and Translation..
Initiation
Elongation
Termination
What is a codon?
A group of three nucleotides that identifies an amino acid.
What are the four types of structures for proteins?
Primary - most basic level of structure of a protein where amino acids create a polypeptide chain
Secondary - way in which a polypeptide chain is folded or coiled
Tertiary - comprehensive three-dimensional shape with a single polypeptide ‘backbone’ with a number of secondary structure ‘side chains’
Quaternary - protein with more than one polypeptide chain
The lipid bilayer is a biological membrane composed of two lipid molecules known as __________.
phospholipids
List the three main components of the lipid bilayer
phospholipids
cholesterol
Glycolipids
The lipid bilayer is composed of ___% Phospholipids, ___% Cholestrol and ___% Glycolipids.
75%
20%
5%
List the two membrane Proteins of the lipid bilayer
Integral - Ion channel, transporter and receptor - extends down across the whole membrane
Peripheral - cell identifier, linker, enzyme - attaches at the outer surface of the membrane
M________ F_________ ensures free rotation and movement of proteins and lipids and allows the lipid bi-layer to self-seal.
M_________ P_________is selectively semipermeable, which means that it allows small, nonpolar, uncharged molecules and water to go through it, but not ions and charged (polar) molecules
Membrane Fluidity
Membrane Permeability
What are the two gradients in cells? Hint one starts with c, the other with e.
concentration gradient
electrical gradient
The concentration gradient is…
the difference in the concentration of a molecule between two sides of the plasma membrane.
The electrical gradient is…
the difference in the electrical charges across the bilayer.
Define the process of facilitated diffusion.
Solutes too polar or large to move across the lipid bilayer by simple diffusion can cross the
plasma membrane by Facilitated diffusion.
Facilitated diffusion is where an integral
membrane protein assists a substance to cross the membrane.
The integral membrane protein
can be either a membrane channel or a carrier.
_______ diffusion is a passive process in which solute moves freely through the lipid bilayer of the plasma membrane of the cell without the help of membrane transport proteins
Simple diffusion
Explain in detail how glucose moves across the membrane utilising facilitated diffusion.
Glucose binds to a carrier protein called a glucose transporter (Glut) on the outside of the
membrane. The transporter undergoes a change in shape and glucose passes through the
membrane. The transporter releases glucose on the other side of the membrane.
Define the process of active transport.
Active transport is the process where energy is required for carrier protein to move solutes across the membrane against their concentration gradient.
There are two sources of cellular energy can be used to drive active transport: Energy from ATP (adenosine Triphosphate) for primary transport and energy stored in an ionic concentration gradient is the source for secondary active transport.
Explain in detail how glucose moves across the membrane utilising active transport.
Glucose is absorbed by into cells by Na+ - glucose symporters, sodium ions move down their
concentration gradient while glucose moves uphill against their concentration gradient.
_________ is the net movement of a solvent (water) through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration or from an area of low solute concentration to an area of high solute concentration.
Osmosis
Passive transport can be affected by:
- The steepness of the concentration gradient: Greater steepness = ______ rate of transport.
- Temperature: _______ the temperature = faster rate of transport.
- Size or mass of the diffusing substance: Greater the size/mass = ______ rate of transport.
- Surface area: Greater the surface area = ______ rate of transport.
- Diffusion distance: Greater the distance = _____ rate of transport.
faster Higher slower faster slower
What are the three (3) types of passive transports?
Simple Diffusion
Facilitated Diffusion
Osmosis
What are the three (2) types of active transports?
Primary
Secondary
In Primary Active Transport energy is derived from the hydrolysis of A____, and this pumps a substance across the plasma membrane against its concentration gradient through a carrier P_____.
ATP, protein
In Secondary active transport uses energy stored in a N_____ or H_____ concentration gradient to drive other substances against their own concentration gradient through carrier proteins (cotransporter).
The gradient is established by/maintained via p______ active transport.
Na+ or H+
primary active transport
