The Cell The building blocks of life
Learning Goals I can describe the cell theory. I can differentiate between a prokaryotic and eukaryotic cell. I can describe the similarities and differences between a plant and animal cell. I can describe the structure and function of the organelles within a cell. I can explain how cells move substances into and out of the cell.
The Cell Every living thing is made up of cells. The human body is made of 10 trillion cells. Cells are factories for producing energy, proteins, other molecules, and other cells.
History of the Cell Throughout history, people have tried to described what makes up living things. In 1665, Robert Hooke describe the first cells in a slice of cork. The first person to describe living cells was Dutch lens maker, Antonie van Leeuenhoek, in 1675.
The Cell Theory The cell theory states: All living things are made of cells. The cell is the smallest living thing capable of carrying out life functions. All cells come from preexisting cells.
The Cell Theory Throughout the next century, the work of three scientists, Dutch botanist Matthias Schleiden (1838), German zoologist Theodor Schwaan (1839), and German doctor Rudolph Virch (1855) helped develop the Cell Theory.
How big is a cell? Cells range in size from the enormous eggs of the ostrich to the smallest bacteria that are around 0.1μm. Most Prokaryotic cells range from 1-10μm. Most Eukaryotic cells range in size from 10-100μm.
Prokaryotic Cell No Nucleus DNA mass in the center of the cell. Contains cytoplasm, ribosomes, and a cell membrane Much smaller than eukaryotic cells
Eukaryotic Cell Eukaryotic cells contain membrane bound organelles. Parts that carry out specific functions. Mini organs Organelles include: Nucleus, ribosomes, mitochondria, Golgi apparatus, Endoplasmic Reticulum, Vacuoles
Plant Cell vs. Animal Cell Plant Cell Chloroplasts A large central vacuole Cell wall Animal Cell No chloroplasts No cell wall No central vacuole Centromere
The Cell Membrane The plasma membrane of both animal and plant cells are essentially the same. A lipid bi-layer Two layers of phospholipids Charged at one end Uncharged on the other.
The Fluid Mosaic Model The membrane is not a rigid, static sheet. The lipids within the membrane move and flow much like a liquid. The components of the membrane determines the viscosity, or how well it flows.
Within the Membrane Within the lipid bi-layer, proteins and other molecules are imbedded. This allows for sites of transport across the membrane. Transport of molecules that can not move via diffusion.
A Selectively Permeable Membrane Due to the polar and non polar ends of the lipids, only certain materials are allowed to pass. This makes the cell membrane selectively permeable. Only certain molecules are allowed to pass. Size and charge are major determiners.
Osmosis and Diffusion Because the cell membrane is selectively permeable, only certain molecules are allowed to cross. The movement of any material is called diffusion. Materials move from areas of high concentration to areas of lower concentration.
Osmosis The movement of water across that selectively permeable membrane is known as osmosis. Water also moves from an area of high concentration to low concentration.
Other types of Transport Facilitated Diffusion- The movement of molecules across the membrane with the help of a protein Active Transport The movement of substances across a membrane that requires energy to happen. Occurs against the concentration gradient.
Other Types of Transport Exocytosis- Release of molecules out of the cell Happens by the fusion of a vesicle with the cell membrane. Endocytosis Pulling molecules into the cell, by making a vesicle.
Endocytosis Pinocytosis The taking in of liquids by a cell Cell drinking Phagocytosis The taking in of solids Cell eating
Cell Anatomy Inside the Cell Membrane
Parts of the Cell Cell membrane, membrane bound organelles, and cytoplasm Cytoplasm- the space between the cell membrane and the nucleus Membrane bound organelle are surrounded by membranes similar to the cell membrane. Nucleus Mitochondria Chloroplasts Vacuole -- Endoplasmic Reticulum -- Golgi Apparatus -- Lysosome -- Ribosomes (no membrane)
The Nucleus The brain of the cell The nucleus contains most of the genetic material (DNA) for the cell. Parts of the Nucleus: Nuclear Envelope Nucleolus Chromatin/Chromosomes
Parts of the Nucleus Nuclear Envelope Double membrane that separates the nucleus from the rest of the cell. Covered with pores that allow the cell to regulate the traffic in and out of the nucleus.
Parts of the Nucleus Nucleolus Structure located inside of the nucleus Where the parts of ribosomes are made and assembled. The number and size of the nucleolus depends on the cell.
Parts of the Nucleus Chromatin Place between the nuclear envelope and the nucleolus Contains the genetic material for the cell Looks like a mass Genetic Material is in the form of Chromosomes as the cell gets ready for division.
The Mighty Mitochondria The cell power plant Bean shaped organelle made of two membranes. The first membrane covers the outside of the organelle. The second membrane is folded into a network called cristae Between the cristae, there is a mass of material called the matrix. Within the Cristae and the Matrix of the mitochondria, the cell performs cellular respiration Breaking down of glucose into CO 2, water, and energy in the form of ATP
Chloroplasts Sugar Factory in Plant Cells Two membrane system with a set of flattened sacs that contain the green pigment, Chlorophyll, and other things necessary for photosynthesis. Within the chloroplasts, plant cells make sugar (glucose) from CO 2 and energy from the sun, a process called photosynthesis.
Chloroplasts Within the inner membrane of the chloroplasts are there are flatted sacs called thylakoids. Stacks of thylakoids are called granula. Between the granula, there is a network of membranes called the stroma Different steps of photosynthesis takes place in each of the portions of the chloroplasts.
Other Plastids Plant cells contain a set of organelles called plastids. Included in this group are the chloroplasts. Usually contain a pigment or other substance Gives flowers and fruit red color Some plastids in roots hold starch
Endoplasmic Reticulum Manufacturing/processing center of the cell. The complex network of membranes produces/processes lipids, hormones, and many other products of the cell. Depends upon the functions of the cell. It also acts as a filter to clean drugs and other chemicals within the cell. Two Types: Smooth ER Rough ER-covered in Ribosomes
Ribosomes Protein Makers of the Cell Reads the code from the DNA to polymerize the amino acids to make proteins. No membrane- Ribosomes are essentially large molecules Made of two pieces Some are free - loose in the cytoplasm Some are bound attached to the rough ER
Golgi Apparatus The packaging, warehousing, sorting, and shipping center for the cell Substances enter on one side of the Golgi, get packaged or finished, then are sent away in a vesicle. A little package that transports the substance to a different organelle, or out of the cell.
Lysosomes Cell Stomach Only a single membrane, contains digestive enzymes Location for digestion of food particles After phagocytosis, a lysosome will attach to the vesicle, dump digestive enzymes, and catabolizes the material. Also digests damaged organelles, acts as clean up crew. Takes in damaged organelles and catabolizes them into their basic parts
Vacuoles Storage system for cells. Varying types have different functions. Food Vacuoles contain food from phagocytosis Contractile Vacuole regulate water in certain protists Central Vacuole large vacuole in plant cells.
Central Vacuole Have many functions in plant cells Stores organic and inorganic compounds Stores by-products from cell metabolism that might be dangerous to the cell Some hold pigments that color cells Some contain poisons against predators Made from the smaller vesicles made by the ER and the Golgi Important in the growth of the plant cells
The Cytoskeleton The cell s support system Also allows for cell movement Three types of fibers: Microtubules Largest Microfilaments (actin filaments) smallest Intermediate filaments middle sized.
The Cytoskeleton Microtubules Hollow rods of protein. Shape and support cell Help certain organelles move around the cell. Also involved in the separation of chromosomes during division. Grow out of the centrosomes Centrioles Set of microtubules arranged in a ring. Only in animal cell Help organize microtubules during division
Cell Mobility Cilia and Flagella Specialized arrangements of microtubules that allow for movement-generally the same arrangement for all cells A core of microtubules covered in an extension of the cell membrane
Cell Mobility Cilia short hair like structures, generally in large numbers on the outside of the cell Around 2-20 μm long Allow cell to move using a beating motion. Also allows for the movement of substances across the cell Cleans materials out of the trachea in humans Flagella Whip-like structure, much longer than cilia 10-200μm long Movement is much like the movement of a snake through water.
Other Types of Cell Mobility Pseudopodia False feet Cell crawls by extending cytoplasm out and pulling itself along Cytoplasmic Streaming Way to flow cytoplasm around cell Occurs mostly in plant cells
The Cell Wall Not in animal cells Thicker than the cell membrane Around 0.1 μm to several μm thick Serve as a structural support for the plant as a whole Made of carbohydrate- cellulose With other polysaccharides and proteins Act to reinforce like steel in concrete