Essays Tagged: "cell membranes"

Determining the concentration of a limewater solution.

AimThis experiment aims to determine the effect an increasing temperature has on a typical plant cell structure.IntroductionCells are surrounded by thin membranes (approximately 5 nm) that separate ... ded by thin membranes (approximately 5 nm) that separate inside from out, life from non-life. These cell membranes perform many functions:·Barrier: membranes keep the contents of the cell toget ...

(12 pages) 79 0 5.0 Sep/2003

Subjects: Science Essays > Chemistry

What is cholesterol?

for clogging up arteries and causing heart disease, this fatty molecule is an essential part of all cell membranes. Scientists have now found to their surprise that cholesterol may also regulate when ... Scientists have now found to their surprise that cholesterol may also regulate when and where nerve cells in the brain form the vital junctions known as synapses.*Cholesterol is a waxy fat that is pre ...

(7 pages) 100 0 3.0 Sep/2003

Subjects: Science Essays > Biology

Biology AT1-osmosis in potatoes.

smosisSkill area PAimTo investigate a factor which might affect the movement of water in and out of cells.IntroductionOsmosis is the movement of water in and out of cell membranes, which act as semi-p ... r in and out of cell membranes, which act as semi-permeable membranes. Semi permeable membranes are cells, which only take in a limited amount of a liquid. The water passes from a region of high to a ...

(6 pages) 40 1 4.0 Oct/2003

Subjects: Science Essays > Biology

Biology Practical to study the Osmosis effects of Sucrose solutions of different Molarities upon Plant Cells (Chinese Radish and Potato Chips)

An Experiment to investigate Osmosis in Plant CellsAimThe aim of this experiment is to investigate the movement of water by osmosis in and out of ... cells across a semi permeable membrane in sucrose solutions of different concentrations. The plant cells used in the experiment are potato and Chinese radish tissues that are used as chips because th ... are used as chips because the results and changes are easy to note and record in this way. As plant cell membranes are differently permeable, different results are expected from the Chinese radish and ...

(26 pages) 78 0 2.3 Jan/2004

Subjects: Science Essays > Biology > Plant Biology

Osmosis and potato chip invetigation. To determine the effect that varying salt concentration, in a solution, has upon the osmotic ability of potato chips of a given size

ecause it can only involve water molecules. However, it is not an isolated laboratory process. Many cell membranes behave as semi/selectively permeable membranes, and osmosis is a vital to their funct ... key mechanism involved in the transportation of fluids in living organisms, such as a plant's root cells. Without the process of osmosis the transport of water from the soil to the roots in plants wo ...

(8 pages) 61 0 3.0 Feb/2004

Subjects: Science Essays > Biology

Essay on bacterial cell wall composition

Bacterial Cell Wall CompositionAlmost all bacteria have cell walls surrounding the cell membranes. This cell w ... l walls surrounding the cell membranes. This cell wall helps to do important functions, like confer cell shape, and protect the cell from lysis when in low solute environments. There are three classif ... cell from lysis when in low solute environments. There are three classifications used in describing cell walls: Gram Positive (Gram+), Gram Negative (Gram-) and Acid-Fast. These membranes share a comm ...

(5 pages) 57 0 4.3 Feb/2004

Subjects: Science Essays > Biology

Investigating the concentration of Glucose inside Cell sap in potatoes Through Osmosis.

In the following experiment I will be investigating the concetration of glucose in the cell sap of a potato cell by weighing the samples of potato before and after soaking them in a conce ... movement of water molecules from an area of high concetration to an area of low concentration. The cell membranes are permeable to water, and so if the glucose concentration inside the cell is more c ... e cell is more concentrated than the solution it's placed in, water molecules will pass through the cell wall to the solution, causing the potato to gain weight.For this experiment I will be using sma ...

(4 pages) 40 0 2.3 May/2004

Subjects: Science Essays > Biology

The Effect Of Temperature On a Cell Membrane's Permeability

hat effect an increase in the surrounding temperature has on the plasma membrane of a typical plant cell structure.Hypothesis:An increase in temperature will damage and denature the plasma membrane an ... oplasm and other substances contained within the membrane to leak out.Introduction:The purpose of a cell membrane is to control the transport of substances moving into and out of a cell. The membrane ...

(5 pages) 111 0 4.7 Jun/2004

Subjects: Science Essays > Biology

Notes on Membrane Structure and Function

rface of water with only the hydrophilic heads immersed in the water*Gorter | Grendel reasoned that cell membranes were two molecules thick (bilayers)*Davson | Danielli proposed the model of a bilayer ... ith various proteins embedded in or attached to a bilayer of phospholipids*Freeze-fracture prepares cells for electron microscopy*Splits a membrane along the middle of the phospholipids bilayer into a ...

(5 pages) 38 0 5.0 Oct/2004

Subjects: Science Essays > Biology

Endocrine system Notes

body.Hormones are chemicals that travel through the bloodstream and affect the activities of other cells. They bind to specific chemical receptors on those cells. Cells that have receptors for a part ... ical receptors on those cells. Cells that have receptors for a particular hormone are called target cells. If a cell doesn't have a particular receptor or receptors that don't respond to the hormone, ...

(8 pages) 121 1 4.3 Nov/2004

Subjects: Science Essays > Biology > Human Biology

AT1- Osmosis In Potatoes

region of low concentration, until the two concentrations are equal in concentrations of water.Many cell membranes behave as semi permeable membranes, and osmosis is a vital mechanism in the transport ... living organisms, for example, in the transport of water from the soil to the roots in plants.If a cell is in contact with a solution of lower water concentration than its own contents, then water le ...

(8 pages) 33 0 3.0 Jan/2005

Subjects: Science Essays > Biology

DNA Lab

Bio 181Lap report#12DNA is a hereditary double helix strands that present in the nucleus of living cells. DNA acts as the blueprint for all of the proteins synthesized by that cell. There are many ch ... kin, blood, semen or hair roots collected at the crime scene, are treated with detergent to rupture cell membranes and obtain DNA for further analysis. DNA from a crime scene can be matched to a suspe ...

(2 pages) 63 0 3.7 Apr/2005

Subjects: Science Essays > Biotechnology

The Plasma Membrane

The cell membrane controls the entry and exit of materials through cells. The main role of cell membrane ... erials through cells. The main role of cell membranes is to: Separate the internal environment of a cell from the external environment, Act as a site for chemical interactions and energy conversions, ... ns and energy conversions, and Detect and bind to substances and initiate biological processes. The cell membrane consists of two layers separated by a very small space of approximately 7-10 nanometer ...

(1 pages) 543 0 0.0 Feb/2006

Subjects: Science Essays > Biology

Proteins

unctioning. First discovered in 1838, proteins are now recognized as the predominant ingredients of cells, making up more than 50 percent of the dry weight of animals. Protein molecules range from the ... bers that make up connective tissue and hair to the compact, soluble globules that can pass through cell membranes and set off metabolic reactions. They are all large molecules, ranging in molecular w ...

(1 pages) 536 0 3.0 Mar/2006

Subjects: Science Essays > Biology

Fats

rature, fats that are liquids are often referred to as oil. In the body, they are stored in special cells named 'adipose' cells, which are located under the skin and near the vital organs of the body, ... body, where it serves to cushion the organs and bones and to provide insulation from the cold. Fat cells are everywhere in the body, however, they are mostly in the abdomen, upper arms and thighs, bu ...

(2 pages) 27 0 2.3 May/2006

Subjects: Science Essays > Biology

Hormones

cretion, however, to include similar regulatory substances that are distributed by diffusion across cell membranes instead of by a blood system. . Among animals, the hormones of the vertebrates--parti ... ormones and the hormones of the thyroid can, as a result of their chemical structures, pass through cell membranes. These hormones apparently enter a target cell and combine with an intracellular rece ...

(4 pages) 53 0 5.0 Jul/2006

Subjects: Science Essays > Biology

What does boiling do to vegetables?

se of the boiling, vitamins are lost. The loss of vitamins is due to the fact that when heated, the cell membranes burst, releasing the ascorbic acid. Vitamin C, the most reactive reducing agent known ...

(2 pages) 14 0 4.0 Aug/2006

Subjects: Science Essays > Biology > Plant Biology

Nucleus, Cytoplasm And Cell Membranes

The nucleus, cell membranes and cytoplasm are all related to one cell or another in a specific way shape or form. ... ell or another in a specific way shape or form. These are what I think are the most important micro cells that support other cells in a way that only pertains to there special traits in functions to t ... his contains all of the protons and neutrons also the negative electrons that are used to keep that cell in working function and to make it do it's function properly and effectively.The nucleus is the ...

(1 pages) 587 0 0.0 Sep/2001

Subjects: Science Essays > Biology

Potassium

Potassium is a very important body mineral, to both cellular and electrical function. Normal growth and muscle building require adequate amounts of pota ... muscle building require adequate amounts of potassium. It governs the actions of the heart, the way cell membranes work, and pathways between muscles and the brain. It caries a tiny electrical charge, ... s a tiny electrical charge, making it an electrolyte. Potassium is one of the bloods main minerals. Cells contain 98% of the potassium in the body, only a small amount is found circulating in the bloo ...

(2 pages) 638 0 0.0 Nov/2001

Subjects: Science Essays > Biology

Caffeine

anpheteminelike stimulant. Caffeine is moderately soluble in water. Caffeine readily passes through cell membranes. After caffeine is ingested it is absorbed from the stomach and intestines into the b ...

(3 pages) 13 0 0.0 Feb/2008

Subjects: Social Science Essays > Controversial Issues > Drugs & Alchohol