Chapter 2 - Cellular Activity Flashcards
What is the role of the cell membrane?
The role of the cell membrane is to seperate the contents of the cell (the intracellular components) from the outside of the cell (the extracellular environment).
What does differentially permeable membrane mean?
It means that the membrane of the cell is able to regulate what goes into and what comes out of, the cell.
What makes up the basic structure of the cell membrane?
- Composed of Phospholipid
- Each Phospholipid has a head (hydrophilic) and a tail (hydrophobic)
- These are arranged into two bilayers
What other things can be found in the Cell membrane?
- Proteins (carbohydrates can be connected to these proteins)
- Channel proteins
- Cholesterol
What are the main functions of the cell membrane?
- A physical barrier:
- The regulation of the passage of materials:
- Sensativity:
- Support
What are the four different membrane proteins?
- receptor proteins
- channel proteins
- carrier proteins
- cell-identity proteins
What is the difference between diffusion and osmosis?
Diffusion is the movement of particles of a liquid or gas, from a high to a low concentration, so that they are evenly distributed over the available space.
Where osmosis is the movement of water molecules through a differentially permeable membrane from an area of hight to low concentration molecules
What is a carrier mediated transport?
Carrier mediated transport is the transport of ions or molecules across a cell membrane by special proteins
What are two examples of carrier mediated transport and describe them.
Facilitated diffusion: Is the process whereby carrier proteins assist the movement of substances through the cell membrane
Active transport: is the use of energy to move substances (usually ions) across the cell membrane
what is vesicular transport?
Vesicular transport is the movement of substances across the cell membrane in membranous bags called vasicles.
what are the two different aspects of vesicular transport?
Endocytosis: which is taking liquid or solids into the cell by vesicular transport
Pinocytosis: talking liquids into the cell
Phagocytosis: taking in solid particles
Exocytosis: when the contents of the vesicle inside the cell are passed to the outside
What is a passive transport and name three transports which are passive.
a passive transport is when there is no energy used in the movement of the molecule.
- Diffusion
- Osmosis
- Facilitated Diffusion
What is an active transport and name three transports which are active.
Is where to make the movement possible the use of energy is required
- Active transport
- Endocytosis
- Exocytosis
What are receptor proteins?
Receptor proteins is a protein in the cell membrane sensitive to certain molecules outside the cell that bind with it
why are receptor proteins specific?
Receptor proteins are specific because there is always a specific molecule which has to ‘fit’ in the receptor protein, not just any molecule can fit.
Why is there variation in the sensativities of cells to hormones and other substances?
This is due to different cells having different types and numbers of receptor proteins
What is the lock and key analogy?
The lock and key analogy refers to the receptor protein having a ‘specific’ molecule to bind to it, exactly like how a specific key opens a specific lock.
What is DNA?
Deoxyribonucleic Acid contains a code that is the inherited information, or genes, that have been passed on from the parent cell.
DNA is made up of…
thousands of nucleotides. Each nucleotide consists of ribose (a 5-carbon sugar), a phosphate group and a nitrogenous base (a base that contains nitrogen atoms).
Name the things which make up the composition of a nucleotide.
- phosphate
- sugar
- nitrogenous base: thymine, guanine, cytosine, adenine
What are protein molecules made out of?
Protein molecules are made out of long chains of amino acid molecules bonded together.
What are ribosomes?
Ribosomes are tiny organelles in the cytoplasm that can read the transcribed code and join the amino acids together in the order specified by the code.
What are the fuctions of proteins?
- structure
- transport across membranes
- communication
- cell metabolism
- recognition
- movement
What is an enzyme?
- Enzymes are molecules that are needed for chemical reactions to take place in living cells.
- All enzymes are proteins
- Therefore DNA determines not only the cells structure but also the way in which the cell functions.
