D1; Analyse the role of the phospholipid bilayer in terms of the movement of materials into and out of cells The phospholipid bilayer is the structure which surrounds a cell, this plasma membrane is made up of two layers of phospholipids; these are the intracellular layer, which is at the bottom, and the extracellular layer which is at the top (Wisegeek.com/bilayer. 2011). The mosaic model shows that the phospholipids are arranged in shapes like heads and tails, the polar heads are made up of glycerol, phosphate and nitrogen and the non-polar tails are made up of fatty acid chains (Wisegeek.com/bilayer. 2011). The polar heads will interact with water as they are hydrophilic, though the tails/fatty acids are never exposed to water therefore they are hydrophobic (Wisegeek.com/bilayer.
The solutes are called electrolytes, which maintain healthy bodily functions. When an electrolyte dissolves it breaks up into ions. There are millions of electrolytes within a cell. Water moves inside and outside the cell, with osmotic pressure, which is the force that pulls fluid from one place to another. The level of osmotic pressure is equal in the intracellular fluid, and the extracellular fluid.’ (Study.com, 2015) ‘Osmotic pressure is vital within the human body because it allows water to enter a cell if there is lack of water, and vice versa, if there is too much water within one cell, the osmotic pressure will allows the electrolytes to exit a cell.’ (Study.com, 2015) ‘Intracellular fluid has important functions, it transports food within the cells, it also brings waste products from the cells so that they can be picked up and excreted from the body, and it maintains the shape and size of the cell.’ (Nursing411.org, 2015) ‘Extracellular fluid is located outside the body cells.
Conditions that must remain constant in this experiment include the temperature of the water baths and the volume of peas and beads in the respirometers. The general gas law states that if temperature and volume remain constant, then the pressure of the gas will change in proportion to the number of molecules of gas present. 2. Water moves into the respirometer pipettes because as oxygen is consumed by the peas, the pressure within the pipettes will decrease and thus the negative pressure will draw the water into the pipette. It is important to correct the readings from the peas because the glass beads are used as a control in which no changes should occur in CO2 and oxygen levels due to their abiotic nature.
How do proteins associate with cell membrane? They associate as either peripheral or integral proteins. Associating as peripheral or integral depends on whether they are hydrophobic and can attach into the bilayer or hydrophilic and must stay on the outside of the bilayer via ionic interactions or H bonds. Integral proteins usually must be removed with detergents. How does the presence of cholesterol affect lipid
A) is neutralized by water B) is surrounded by water molecules C) reacts and forms a covalent bond to water D) aggregates with other molecules or ions to form a micelle in water Answer: B Page Ref: Section 3 11 9) Which would you expect to be most soluble in water? A) I B) II C) III D) IV Answer: A Page Ref: Section 3 10) Solutes diffuse more slowly in cytoplasm than in water because of A) the higher viscosity of water. B) the higher heat of vaporization of water. C) the presence of many crowded molecules in the cytoplasm. D) the absence of charged molecules inside cells.
Compounds called proteins and phospholipids make up most of the cell membrane. The phospholipids make the basic bag. The proteins are found around the holes and help move molecules in and out of the cell. Cell Membrane A cell membrane of the cell. It gives the cell its shape, it is the outer covering of the cell made up from phospho-lipid-protein bi-layer, which allows the materials to enter and to exit.
Laura Mccain Lab 5: Osmosis with Hypertonic, Isotonic and Hypotonic tonicity Purpose: The purpose of this lab is to familiarize you with osmosis and, specifically, what happens to cells when they are exposed to solutions of differing tonicities. Hypothesis: Hypotonic Solution: the cell has a higher concentration in it than in the area surrounding it. Water moves into the cell to equal out concentration. Isotonic Solution: The cell has a equal proportion of concentration with the area surrounding. Water continually flows in and out to keep concentration even.
| | | A) | endoplastic reticulum | | | B) | microtubules | | | C) | cytoplasm | | | D) | mitochondria | | | | | | Feedback: The cell's chemical processes take place in a semifluid material called the cytoplasm. This material provides an ideal environment for organelles because of its fluidity. | | 7 CORRECT | | This shows an example of endoplasmic reticulum. What is the significance of its structure? | | | A) | provides a location for DNA production | | | B) | helps decrease surface area | | | C) | allows selective permeability of cell membrane | | | D) | facilitates breakdown of chemical bonds | | | | | | Feedback: The pleats and folds of the endoplasmic reticulum provides a large surface area where cellular functions, such as breaking chemical bonds, can take place.
Understand the interactions of actin and myosin in muscle contraction and in “localized” muscle contraction (e.g. pseudopodia and cytoplasmic streaming) Understand the structure and function of cell walls in plants. What other kinds of cells have them? What kinds of molecules make up the extracellular matrix in animals? Where do they come from?
- Osmosis only moves water across a semi-permeable membrane. 3.5 Distinguish between active and passive transport and relate these to the processes occurring in the mammalian kidney. - Active transport uses energy to move materials across membranes. - The secretion of some ions into the convoluted tubules of the kidneys. - Passive transport does not require an energy input.