SC10-WEEK6-CELL FUNCTIONS AND STRUCTURE

CELL FUNCTIONS AND STRUCTURE

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Did you know that a first step toward the scientific understanding of cell membranes was Benjamin Franklin's experiment in 1774 of pouring oil into a pond of water?

Shape and size of cells

Cell Structure

About procarotic cells

On the outside of the plasma membrane of the prokaryotic cell is the cell wall, which protects the cell from external changes. The interior of the cell is much simpler than in eukaryotes; Ribosomes are found in the cytoplasm, with practically the same function and structure as eukaryotes but with a lower sedimentation coefficient. Mesosomes are also found, which are invaginations of the membrane.

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The membrane and cytoplasm

Transport through the membrane

In order to live, the cell needs to exchange substances with the external environment. There are two ways to transport the substances: PASSIVE TRANSPORT: refers to a fundamental cellular mechanism that allows the movement of substances across the cell membrane without the use of energy (ATP). This transport can be given by: ACTIVE TRANSPORT: the transport of substances takes place against their electrochemical gradient, so an expenditure of energy is always required, in the form of ATP, which is hydrolyzed. Carrier proteins are called pumps. The Na+ and K+ pump is an example of active transport.

Cell Organelles

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The outer layer of a cell, or cell membrane, is a complex structure with many different types of molecules that are in constant motion and move fluidly across the membrane.

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Welcome 6th graders!

10TH-CELL FUNCTIONS AND STRUCTURE-EN © 2024 by CASURID is licensed under CC BY-NC-ND 4.0

• Facilitated diffusion involves molecules that cannot easily cross the lipid bilayer due to their size or charge. These molecules require the help of carrier proteins or protein channels to cross the cell membrane.

THE ENDOMEMBRANE SYSTEM: it is the set of interconnected membranous structures (organelles) that can occupy almost the entire cytoplasm.

GENETIC MATERIAL: made up of one or more DNA molecules. Depending on whether or not it is surrounded by a membrane, forming the nucleus, two types of cells are differentiated: prokaryotes (without a nucleus) and eukaryotes (with a nucleus).

ENERGY TRANSDUCING ORGANELLES: these are the mitochondria and chloroplasts. Its function is the production of energy from the oxidation of organic matter (mitochondria) or light energy (chloroplasts).

PLASMA MEMBRANE: made up of a lipid bilayer in which certain proteins are encompassed. Lipids act as an insulating barrier between the internal aqueous medium and the external aqueous medium.

The cell is a structure made up of three basic elements: plasma membrane, cytoplasm and genetic material (DNA). Cells have the ability to perform all three vital functions: nutrition, relationship, and reproduction. The shape of cells is basically determined by their function. The shape can vary depending on the presence or absence of a rigid cell wall. Cell size is also extremely variable. The factors that limit their size are the capacity to capture nutrients from the environment that surrounds them and the functional capacity of the nucleus.

The structure common to all cells comprises the plasma membrane, cytoplasm, and genetic material or DNA.

MEMBRANE-LESS STRUCTURES: they are also in the cytoplasm and are the ribosomes, whose function is to synthesize proteins; and the cytoskeleton, which gives hardness, elasticity and shape to cells, as well as allowing the movement of molecules and organelles in the cytoplasm.

SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport). SC.912.L.14.20 Identify the major muscles of the human on a model or diagram.

If you want to know a little more about what Benjamin Franklin did, here is this video

• Simple diffusion is a process by which small, nonpolar molecules, such as oxygen and carbon dioxide, move freely through the lipid bilayer of the cell membrane, from areas of high concentration to areas of low concentration.

THE CYTOPLASM: encompasses the liquid medium, or cytosol, and the morphoplasm that contains the cellular organelles.

THE NUCLEUS: it keeps the genetic material protected and allows the functions of transcription and translation to occur independently in space and time.