| Question |
Answer |
| How does a light microscope function? |
Light passes through a specimen and then through a lens |
| How does a scanning electrin microscope work? |
A beam of electrons is focussed onto the surface of a specimen |
| How does a transmission electron microscope work? |
A beam of electrons is focussed through a specimen |
| What is magnification? |
The ratio of image size to life size |
| What is resolution? |
Measure of clarity of an image |
| What is contrast? |
Visible differences in parts of an image |
| What is cell fractination? |
Seperation of major organelles from one another when a cell is taken apart |
| What are the major differences between prokaryotic and eukaryotic cells? |
Eukaryotes- have membrane bound organelles and nucleus Prokaryotes- don't |
| What is the plasma membrane? |
Permeably selective barrier of phospholipids that surrounds the cell and regulates flow of substances |
| What is the nuclear lamina? |
Protein composed organelle that maitains the shape of the nucleus |
| What is the nucleolus? |
Site of RNA synthesis inside the nucleus |
| How are chromosomes formed? |
Chromatins condense |
| What is the function of a ribosome? |
Protein synthesis |
| What are the components of the endomembrane system? |
Nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuolas, plasma membrane |
| What connects or transfers information through the endomembrane system? |
Vesicles |
| What is the difference between smooth and rough er? |
Rough ER is studded with ribosomes, smooth ER is not |
| What are some functions of smooth ER? |
Synthesize lipids, detoxifies poison, stores calcium |
| What are some functions of the rough ER? |
Secrete glycoproteins, distributes transfer vesicles, creates membranes |
| What are some functions of the golgi apparatus? |
Modidfies products of the ER, manufactures macromolecules, sprts and packages materials in transport vesicles |
| What is the function of a lysosome? |
Digesting macromolecules |
| What is phagocytosis? |
A cell engulfing another cell to from a food vacuole |
| What do contractile vacuoles do? |
Pump excess water out of cells |
| What do central vacuoles contain? |
Organic compounds and water |
| What do mitochondria do? |
Generate ATP by cellular respiration |
| What do chloroplasts do? |
Photosynthesis |
| How do mitochondria and chloroplast differ from pieces of the endomembrane system? |
have a double membrane, have proteins made by free ribosomes, contain their own DNA |
| What is the structure of chloroplast? |
Thylakoids stacked to form granum and surrounded by internal fluid called stroma |
| What organelle performs oxidation and what does oxidation do? |
Peroxisomes use oxidation to break down molecules |
| What is the cytoskeleton? |
Network of fibers extending throughout the cytoplasm |
| What are some functions of the cytoskeleton? |
Supports cell structure, provides paths for vesicles, produces mobility by interaction with motor proteins |
| What are microtubules? |
Hollow rods that shape the cells, guide organelle movement, and seperate chromosomes |
| What is the centrosome? |
Organizing center of microtubules near the nucleus |
| What are two types of motor appendages controlled by microtubules? |
Cilia and flagella |
| What is the motor protein which drives cilia and flagella? |
Dynein |
| What are microfilaments? |
Thin solid rods built as twisted double chains if actin subunits |
| What is the function of the microfilament? |
Forming a cortex to maintain cell shape by resisting pulling movements |
| What protein is found in microfilaments along with actin? |
Myosin |
| What is cytoplasmic streaming? |
Circular flow of cytoplasm through the cell that speeds diffusion |
| What is the mid-sized cytoskeleton structure and what is its function? |
Intermediate filaments- fix organelles in place |
| What is a cell wall? |
Extracellular structure that distinguishes plant cells from animal cells |
| What three layers can be found in the cell wall? |
Primary cell wall, midlle lamella, and secondary cell wall |
| What is the extracellular matrix? |
Elaborate system of connections between animals cells by extracellular structures |
| What are the functions of the extracellular matrix? |
Support, adhesion, movement, and regulation |
| What are intercellular junctions? |
Neighboring cells communicatinos through direct contact |
| What are plasmodeta? |
Channels that perforate cell walls and allow water and small solutes to pass from cell to cell |
| What are tight junctions? |
Membranes of neighboring cells pressed together to prevent leaking of extracellular fluid |
| What are demosomes? |
Fastenings of cells into strong sheets |
| What are gap junctions? |
Cytoplasmic channels between adjacent cells to allow communication |
Ch.18 LTI-MA 509
