Molecules B-LS1-8 PDF

Molecules B-LS1-8 Cell Theory The Cell Theory states: 1. Cells are the basic unit of life 2. All living organisms are made up of cells 3. All cells come from preexisting cells Cell Organelles Eukaryotic cells have specialized substructures, called organelles, carry out the essential functio...

Molecules B-LS1-8 Cell Theory The Cell Theory states: 1. Cells are the basic unit of life 2. All living organisms are made up of cells 3. All cells come from preexisting cells Cell Organelles Eukaryotic cells have specialized substructures, called organelles, carry out the essential functions of life. These are organelles you should already be familiar with. Let’s refresh our memory ○ Cytoplasm ○ Cell Membrane ○ Cell Wall ○ Mitochondria ○ Chloroplasts ○ Lysosomes ○ Vacuoles Organelles Cytoplasm -The gel-like fluid inside of a cell made of mostly water. Cell membrane -The thin, flexible outer covering of a cell. It controls what enters and leaves a cell. Cell wall - Provides support and shape for plant cells. It is made mostly of cellulose which provides a protective framework for the cell Organelles Mitochondria – The energy producing sites in the cell where cellular respiration takes place (sometimes called the “powerhouse” of the cell). ATP is created here Chloroplasts - Contains chlorophyll, the green pigment that absorbs light energy in order to produce glucose (food) for the plant. Lysosomes -Organelles responsible for digesting certain materials within the cell such as food, worn out organelles, as well as other cellular waste not needed for cell Vacuole – The temporary storage centers. for water, minerals, or waste products until they can be eliminated from the cell.  Organelles Continued - Nucleus Nucleus - contains the chromosomes which are composed of DNA (deoxyribonucleic acid, a chemical compound that stores and transmits genetic information); and functions in the genetic control of the cell. ○ A chromosome is a structure in the nucleus of a cell consisting essentially of one long thread of DNA that is tightly coiled. Organelles Continued - Cytoskeleton Cytoskeleton - is a network of fibrous proteins that helps the cell with maintaining shape, support, and movement. Organelles Continued - Endoplasmic Reticulum (ER) Endoplasmic Reticulum - is a complex, extensive network that transports materials throughout the inside of a cell. ○ Rough ER has ribosomes attached to the surface. ○ Smooth ER has no ribosomes attached. Organelles Continued - Ribosomes Ribosomes - are the sites of protein synthesis (creation of proteins); some are located on the ER, others are found in the cytoplasm. Organelles Continued - Golgi Complex/Apparatus/Body Golgi complex - collects, packages, and otherwise modifies cell products (for example proteins and lipids) for distribution and use within or outside the cell Organelles Continued - Vesicles Vesicles - carry proteins from the rough ER to the Golgi apparatus. Proteins and Cell Function Cellular processes are carried out by molecules. Proteins carry out most of the work of cells to perform the essential functions of life. One of the major functions of the cell is the production of proteins. The genetic information in DNA provides instructions for assembling protein molecules. In eukaryotic cells the nucleus, ribosomes, endoplasmic reticulum, vesicles, and the Golgi apparatus interact to produce, modify and transport proteins. Prokaryotic vs. Eukaryotic Prokaryotic and eukaryotic cells share several similarities which include the presence of ribosomes, cytoplasm, genetic material, and a cell membrane. Prokaryotic vs. Eukaryotic The major difference between prokaryotic cells and eukaryotic cells is the presence of a true nucleus. Prokaryotic cells do not have a true nucleus; the DNA in prokaryotic cells is not completely separated from the rest of the cell. They don’t have a nuclear membrane (envelope) and most prokaryotic cells have a singular circular chromosome. ○ In other words…genetic information in these cells are “free floating” Eukaryotic cells contain DNA which is organized into linear chromosomes, and the chromosomes are separated from the cytoplasm by a nuclear membrane. ○ In other words…genetic information in these cells are “contained inside and organized” Prokaryotic vs. Eukaryotic Prokaryotic cells differ from eukaryotic cells in other ways: Prokaryotic cells lack most of the other membrane bound organelles that are present in the cytoplasm of eukaryotic cells. ○ Prokaryotic cells do not contain mitochondria but they can obtain energy from either sunlight or from chemicals in their environment. Prokaryotic cells are generally much smaller than eukaryotic cells. Prokaryoitc organisms can reproduce asexually Prokaryotes such as bacteria are unicellular organisms. Plant Cells Plant cells contain almost all the types of organelles that animal cells contain, but plants have three unique structures that are not found in animal cells: ○ The cell wall, the central vacuole, and plastids such as chloroplasts. Why do we think plant cells have these organelles and animal cells do not? Fungal Cells Fungal cells have a cell wall that is made of chitin and other polymers instead of cellulose; they may have several nuclei within a single cell. Fungal cells cannot make their own food through photosynthesis because they lack chloroplasts. Viruses Viruses are non-living particles made up of a nucleic acid and either a protein or lipid-protein coat. ○ Considered non-living because they are not composed of cells. Viruses are organized, can replicate and respond. They cause many diseases in living organisms and are useful tools for genetic research. Viruses are extraordinarily small; smaller than prokaryotic cells. Viruses Viruses do not have cytoplasm or organelles and thus cannot carry out cell functions such as metabolism. They cannot grow by dividing. To reproduce, viruses must enter a living cell and use that cell’s (the host cell’s) ribosomes, enzymes, ATP, and other molecules to reproduce. ○ Swine Flu 2009 ○ Ebola Virus 2014 ○ Coronavirus 2019 How does Coronavirus enter your body?