Bio 100- Chapter 4

light projected though the specimen. Lenses enlarge the image of project to human eye. Used to explore living cells.- magnifies up to 1,000x, generally used to study general appearance. reducing the amount of light, will actually increase the contrasts and make it easier to see clearly.

1500's by Zacharias Janssen

1600's credited for viewing first cell- latin word "cella"

increase in object's apparent size

ability of an optical instrument to show 2 objects as separate, clarity depends on this.

uses a beam of electrons to resolve objects. better resolving power than light microscope. Two kinds- SEM (scanning electron) and TEM (transmission electron)

used to study detailed architecture of cell surface- magnifies specimens up to 10,000x, 3 dimensional views of cells are accomplished

used for exploring the internal structure of the cell. Magnify up to 100,000X

will be killed and preserved to view.

bounded by thin outer membrane, plasma membrane, all cells have DNA, and all have ribosomes

regulates traffic of molecules between the cell and its surroundings.

tiny structures that build proteins according to instructions from the DNA.

prokaryotes are older in an evolutionary sense, prokaryotes are smaller and simpler in structure. Eukaryotic cells only have organelles

"little organs" membrane-enclosed structures that perform specific functions. Most important is nucleus.

houses most of eukaryotic cell's DNA and is surrounded by a double membrane.

Prokaryotic cell lacks a nucleus, DNA will be housed in nucleoid which isn't separated from rest of the cell.

Like an open warehouse.

Surrounding the plasma membrane is a rigid cell wall that protects and helps keep shape.

Sticky outer layer called capsule to help stick.

Some have Pili and flagella.

entire region of the cell between the nucleus and plasma membrane (interior of prokaryotic cell). Consists of various organelles suspended in fluid.

protective cell wall outside the plasma membrane.

Don't have centriole, lysosome, flagellum

Doesn't have central vacuole or cholorplast or cell wall.- most have a extracellular matrix (sticky coat)that holds cells together in tissues and can also protect and support. Surface contains cell junctions-structures that connect to other cells- allow cells in a tissue to function in a coordinated way.

the organelles that convert light energy to the chemical energy for food- present in plant cells not animal cells.

composed of mostly lipids and proteins

special category of lipids, related to dietary fats but have only 2 fatty acids tails instead of 3, in place of third, a phospholipid has a phosphate group (phosphorous and oxygen)- this is electrically charged , water loving (hydrophilic)- but the 2 tails are hydrophobic

Good membrane material.

2 layered membrane, hydrophobic tails of the molecules stay away from water, hydrophilic heads remain surrounded by water. embeded in are proteins that help regulate traffic across the membrane and perform other functions.

membrane, proteins are free to drift about in plane of membrane

protect, keep shape and keep cells from absorbing so much water (plant cells)

Do most of the work

nucleus is bordered by a double membrane. Each membrane is similar in structure to the plasma membrane. Pores in the envelope allow certain materials to pass between nucleus and cytoplasm.

fibers that are formed within the nucleus by DNA molecules and associated proteins.

each long chromatic fiber contains a chromosome. human body cell has 46, rice have 24 and dog cells have 78

prominent structure within the nucleus, is the site where the components of the ribosomes are made.

small dots in the cells. responsible for protein synthesis. In eukaryotic cells, the components of ribosomes are made in the nucleus then transported through pores into cytoplasm,others are attached to outside of organelle

DNA programs protein production by transferring coded info to RNA, then RNA carried out order to build protein from the nucleus to cytoplasm

organelles from this. connected organelles- system includes golgi apparatus, lysosomes, vacuoles, endoplasmic reticulum and nuclear envelope

main manufacturing facilities in a cell. produces an enormous variety of molecules. From a labyrinth of tubes and sacs running through the cytoplasm. Connected to nuclear envelope. 2 components that make up the ER- Rough and Smooth ER- physically connected by differ in structure and function

appearance of organelle, due to ribosomes that stud the outside of the ER membrane. these produce membrane proteins and secretory proteins. One function is to produce new membrane. Cells that secrete a lot of protein (saliva) are especially rich in rough ER.

membranous spheres that bud from the rough ER

lacks the ribosomes that populate the surface of rough ER. Function is the synthesis of lipids- example- can make certain antibiotics less effective

refinery, warehouse, and shipping center for chemical products of the cell.

sac of digestive enzymes found in animal cells. (absent from plant cells)- develop from vesiles that bud off from the gogli. Enzymes can break down large molecules such as proteins, fats and nucleic acids. provides compartment where the cell can digest these molecules safely, without unleashing these digestive enzymes on the cell itself.

several functions: many engulf nutrients into tiny cytoplasmic sacs called food vacuoles. Lysosomes fuse with the food vacuoles, exposing the food to enzymes that digest it. Also help destroy harmful bacteria, break down large molecules of damaged organelles

sacs that bud from the ER, gogli or plasma membrane. Multifuctional: freshwater protists have contracile vacuoles that pump out water that flows in from cell.

is a versatile compartment, stores organic nutrients, contributes to plant growth, may also contain poisons that protect againist plant eating animals

organelles that perform photosynthesis. Unique to cells of plants and algae- 3 major compartments.

1. cholorplast-space between 2 membranes

2. stroma- a thick fluid within the chloroplast

3. grana- solar power packs, trap light energy and covert it to chemical energy.

sites of cellular respiration, process that harvests energy from sugars and other food molecules and coverts it to another form of a chemical energy called ATP.

thick fluid

network of fibers extending throughout the cytoplasm- skeleton and muscles for the cell, maintain shape, support cell.

fiber, straight, hollow composed of proteins located in cytoskeleton.

motile appendages, aid in movement. Flagella propel the cell by undulating whiplike motion. Cilia promote movement by back and forth.

two sets of glass lenses are used to magnify the specimen.