ciencias

homework

Homework:

What is active transport?

Answer:Active transport is the mediated process of moving molecules and other substances across membranes.
what is passive transport?

Passive transport or diffusion. Passive transport is the simple exchange of molecules of a substance across the plasma membrane, during which no expenditure of energy that provides the cell.
What is concentration gradient?

Concentration gradient is the difference in solute concentration between two solutions or media.An example: you have water in a container to which you add salt, but do not shake, by the time you add the salt, the highest concentration of salt will be at the bottom of the container, while the higher the concentration is minimal. This difference is the gradient.
what is osmosis?

Osmosis is a physical-chemical phenomena related to the behavior of water as a solvent for a solution to a semipermeable membrane for the solvent (water) but not solutes. Such behavior involves a simple diffusion through the membrane, without "spending power". Osmosis is an important biological phenomenon for cellular physiology of living beings.

What is broadcast?

Diffusion is a physical process irreversible, in which material particles are introduced into an environment that was initially absent, increasing the entropy of the joint formed by the scattered particles or solute and the environment in which diffuse or solvent.
Usually diffusion processes are subject to the Fick's law. The permeable membrane may allow passage of particles and solvent always in favor of concentration gradient. The release process requires no energy input, often as a form of cellular exchange.

lunes, 1 de marzo de 2010

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Homework

Homework :

1)How is formed the cell membrane?

Plasma membrane prokaryotes, eukaryotic cell membrane, phospholipid membrane, selectively permeable cell membrane,
cell wall membrane, plasma membrane cytoplasm cell membrane pores, membrane substances.

2) As it is called the model explains the structure of the cell membrane?

The fluid mosaic model is, in biology, a model of plasma membrane structure proposed in 1972 by S. J. Singer and Garth Nicolson thanks to advances in electron microscopy.

3) Who discovered the cell membrane model?

In 1972, Singer and Nicholson proposed the fluid mosaic model. This was possible thanks to advances in electron microscopy, the hydrophilic interaction study, the study of noncovalent bonds such as hydrogen bonding and the development of techniques such as contrast criofractura and negativo.

S. Jonathan Singer

Garth Nicolson

lunes, 22 de febrero de 2010

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transporte de membrana

Membrane Transport: The cell biology of membrane transport is called the set of mechanisms that regulate the passage of solutes, such as ions and small molecules across cell membranes, ie lipid bilayers that have proteins embedded in them.

Mind is a selective permeable barrier, since it prevents the free exchange of materials from one place to another, but at the same time provide a means for communicating a space with another;

Allows the passage or transport of solutes from one side to another cell, it regulates the exchange of substances between the interior and exterior of the cell down a concentration gradient;

sábado, 20 de febrero de 2010

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Class: 3

Date: February. Tuesday 16/10

Item: Review the cell

Robert Hooke:

Jean baptiste von helmont: created the first microscope; and saw a drop of water and discover the protist.

Matias Schleiden

= developed the cell theory.

Theodor Schwann

Cell Theory

Its has three postulates.

1. The cell is unity of structure.

2. The cell is unity of function.

3. All the living things are formed by cells.

The Cell

Parts

Nucleus: Is a structure inside

The cell: its function is the control and direction of the cell. The nucleus is formed By:

nucleolus: Its function is to do ribosomes.

Nuclear Membrane: Its formed by phospholipids and proteins.

Its function is give shape to nucleus.

inside of the nuclear membran we can find NUCLEAR JUICE.

The nuclear juice: Its a liquid made by DNA and RNA

Ribosomes: They are in all places of the cell; they was created in the nucleus. The ribosomes produce proteins that are used in the construction of the membranes.

Chromosomes: They are responsible by the genetic information.

Celular Membrane

Is a structure most important; their functions are:

- Protect the nucleus and cytoplasm

- Give form to the cell

-To allow change of nutrients

martes, 16 de febrero de 2010

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matthias jakob schleiden

Matthias Jakob Schleiden
Born in Hamburg, Schleiden was educated at Heidelberg and practiced law in Hamburg, but soon developed his hobby of botany into a full-time pursuit. Schleiden preferred to study plant structure under the microscope. While a professor of botany at the University of Jena, he wroteContributions to Phytogenesis (1838)