Upload
evania
View
65
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Lesson # 11. LIFE’S HOME:. The Cell. Atoms. Molecules . Organelles. Cells. Atoms combine to form molecules. Small molecules: water Macromolecules: DNA, proteins. Highly organized structures with one special function. Ex: mitochondria, ribosomes. - PowerPoint PPT Presentation
Citation preview
LIFE’S HOME:Lesson # 11
The Cell
Atoms Molecules Cells
OrgansTissues Organisms
Organelles Atoms combine to form molecules
Small molecules: water Macromolecules: DNA, proteins
Highly organized structures with one special function. Ex: mitochondria, ribosomes
Each cell contains hundred of organelles. They can do all things listed previously. Life actually occurs in cells
A collection of cells that serve a common function. Ex: muscle tissue.
A functioning unit formed by several kinds of tissues. Ex: The heart, a blood vessel, the brain
Organisms can be formed by only one cell ( bacteria) or trillions of cells organized in organ systems (human).
Organ SystemsDifferent organs that work together closely. Ex: Cardio- vascular system, respiratory system, nervous system
Community BiospherePopulationMembers of a single type of living thing (species), living in one area.
All the kind of living things in a given area (several species).
EcosystemThe community of organisms plus all the non-living elements
The interactive collections of all the Earth’s ecosystems
All Cells Are Either Prokaryotic or Eukaryotic
Cells
-They have no nucleus.
-They have a membrane-bound nucleus.
- Usually are smaller
- Usually are larger
- Single-celled organisms
- Often multicellular organisms
- No membranous organelles
- Membranous organelles
Prokaryotic cells (bacteria and archaea)
Eukaryotic cells (plants, animals and fungi)
Prokaryotic cells Eukaryotic cells
DNA
Size
Organization
Organelles
in “nucleoid” region within membrane-bound nucleus
much smaller much larger
always single-celled often multicellular
only one type of organelle many types of organelles
Prokaryotic and Eukaryotic Cells Compared
The human body has 50 to 100 trillion cellsThe trillions of cells in the human body include over 200 different cell types
The Eukaryotic Cell
Nucleus
Organelles
Cytosol
Plasma membrane
Cytoskeleton
Proteins are assembled in the ribosomes, which are in the cytoplasmThe instructions for the assembling are in the nucleus
Along the Protein Production Path
Nucleus
Ribosomes
Rough endoplasmic reticulum
Golgi complex
Plasma membrane
Nuclear envelope
THE NUCLEUS
Functions1- It contains the DNA, which contains all the information for protein synthesis
2- It is the place where the DNA duplicates
3- It contains the nucleolus where the ribosomes are produced
THE NUCLEOLUSIt is the area within the nucleus where the ribosomes are produced
Nucleolus
1- They are the organelles that serve as the site of protein synthesis in the cell
THE RIBOSOMES
2- Ribosomes are not lined by a membrane
3- Ribosomes are made of ribosomal RNA ( rRNA ) and proteins
4- Ribosomes are produced in the nucleolus
Types of RNA
Ribosomal RNA ( rRNA )Messenger RNA ( mRNA )Transference RNA ( tRNA )
1- Ribosomal RNA ( rRNA ): it is structural part of the ribosomes
rRNA + proteins
2- Messenger RNA ( mRNA ): It carries the instructions from the DNA to the cytoplasm for the synthesis of proteins
mRNA
3- Transfer RNA ( tRNA ): Select and transport the aminoacids to be incorporated in the polypeptide chain
tRNA
mRNA
tRNAAminoacids
The Rough Endoplasmic Reticulum It is a network of membranes that collect the proteins assembled in the ribosomes and transfer them to the Golgi complex
Golgi Complex
Rough Endoplasmic Reticulum
The Golgi ComplexIt is a network of membranes that process and distribute proteins that come to it from the rough endoplasmic reticulum
The Smooth Endoplasmic Reticulum It is a network of membranes that is the site of synthesis of various lipids and where harmful substances are detoxified within the cells.
Smooth endoplasmic
reticulum
The Smooth Endoplasmic Reticulum
1- It is farther form the nucleus
2- It does not contain ribosomes
3- It is the site where lipids are synthesized ( triglycerides, steroid hormones, etc)
4- It is the site where harmful substances are detoxified within the cells
The Lysosomes
They are organelles that digest worn-out cellular materials and foreign materials that enter the cell.
The lysosomes contain about 40 different enzymes, in an acidic medium, that can break larger molecules into their component parts.
The lysosomes digest bacteria that enter the cells and also damaged organelles that exist inside the cells.
The MitochondriaThey are the site of the cell where energy from food is converted to ATP
ATP
ATP
The Cytoskeleton
It is a network of protein filaments, which has the following functions:
1- Maintain the cell structure ( scaffolding)
2- It is involved in cell movement
3- Transport of materials within the cell
Common Structures in Animal and Plant Cells
Cell wall
Central vacuole
Plastids
Differences Between Plant and Animal Cells
Cell wall Limit water uptake, maintain cell membrane shape, protect from outside influences
Central vacuole
Cell metabolism, pH balance, digestion, water maintenance
PlastidsNutrient storage, pigmentation, photosynthesis
( chloroplasts )