Chapter Six Flashcards
What are the 3 main properties of a microscope that influence the image?
magnification, resultion, contrast
What is magnification?
ratio of image size actual size; multiplication factor of size
What is resolution?
minimum distance two points can be separated and still be distinguished as separate points; image clarity
What is contrast?
difference in brightness between light and dark areas of an image
What are the 3 main types of microscopes?
compound light microscope, disseecting/stereo microscope, electron microscope
Which microscope inverts an image?
compound light microscope
How many SETS of lenses does a compound light microscope use to magnify an image?
2
Which microscope requires a specimen to be stained before use? Why?
compound light microscope; since cells are usually transparent
What is the magnification of a compound light microscope?
400x (1000x with oil immersion)
What is the best resolution of a compound light microscope?
0.2 micrometers
What view (of a sample) does a compound light microscope provide?
thin 2D view of sample
What is the magnification of a dissecting/stereo microscope?
20x-80x
What view (of a sample) does a dissecting/stereo microscope provide?
3D view of sample
What are the two types of electron microscopes (EM)?
scanning EM, transmission EM
In a scanning EM, electrons move ____ ___ _____ across a specimen
back and forth
Scanning EM renders details by __________
reflection
In a transmission EM, electron beams are….
transmitted through a specimen
Transmission EM provides….
details of internal structures
Electron microscopes have a ______ magnification and resolution
higher
What are the three domains of living organisms?
archaea, bacteria, eukarya
What are archaea?
single celled organisms without a nucleus, extremophiles, prokaryotes
formerly grouped with bacteria
What are bacteria?
all other prokaryotes aside from archaea
What are the kingdoms of eukarya?
animalia, plantae, fungi (FORMERLY protists)
What are cells?
basic unit of structure and function in a living organism
Prokaryotes are generally _______ than eukaryotes. Why?
smaller; prokaryotes are single-celled
Prokaryotes or Eukaryotes: Which has a nucleus?
Eukaryotes
Prokaryotes or Eukaryotes: Which has organelles?
Eukaryotes
What are the 4 common components of all cells?
plasma membrane, cytoplasm, chromosomes, ribosomes
What is the plasma membrane?
outer covering separating the
cells interior from its surroundings
What is the cytoplasm?
area between cell membrane, nucleus, and all components within this area
largely filled with cytosol: jellylike
What are chromosomes?
carry genes in the form of DNA (genetic material)
What are ribosomes?
particles that synthesize proteins
Characteristics of prokaryotic cells
- No nucleus but a nucleoid region
- Smaller
- Single celled
Characteristics of eukaryotic cells
- Nucleus and other membrane bound organelles
- Single or multi-celled
- Usually larger
What is the plasma membrane?
phospholipid bilayer with embedded proteins
What does the plasma membrane do?
- separates internal contents from the surrounding environment
- regulate the passage of many substances; semipermeable
What is the benefit of the plasma membrane being semipermeable?
helps maintain internal condition
The _____ is typically the largest organelle
nucleus
What does the nucleus do?
- store DNA (chromosomes)
- direct synthesis of ribosomes and proteins
What is chromatin?
DNA and proteins that form chromosomes
What is the nucleolus?
area where ribosomal RNA (rRNA) is produced
What is the nuclear envelope?
double membrane forming outermost portion of the nucleus
What does the nuclear envelope do?
controls passage of ions and molecules between the interior of the nucleus and cytoplasm
What are ribosomes?
structures that make proteins
True organelles must be _____ _________
membrane bound
Which ribosomes (free or bound) are suspended in cytosol and make proteins utilized in cytosol?
free
Which ribosomes (free of bound) are embedded in the ER and make proteins that are inserted into membranes or packed into organelles?
bound
What is the endomembrane system?
group of membranes and membrane bound organelles
What does the endomembrane system do?
- direct connection or transfer via vesicles
- synthesis/transport of proteins
- metabolism and movement of lipids
- detoxification of poisons
What is included in the endomembrane system?
- smooth ER
- rough ER
- golgi apparatus
- lysosomes
- vacuoles/vesicles
What is the rough ER?
interconnected membranous tubules and sacs connectedd to the nuclear envelope
What does the rough ER do?
- modify proteins and synthesize lipids
- assist in making membranes
What is the smooth ER
interconnected membranous tubules
What does the smooth ER do?
- makes lipids, steriod hormones, and carbohydrates
- detoxifies medicines and poisons
- stores calcium ion
The _____ _______ is assosciated with the endoplasmic reticulum (ER)
golgi apparatus
What does the golgi apparatus do?
- sorts, tags, packagaes, and distributes lipids and protiens
- synthesizes polysaccharides in plants
Cis or trans: ____ face recieves vesicles from the ER
cis
Cis or trans: ____ face sends vesicles to other areas
trans
What are lysosomes?
the cell’s garbage and recycling center
What do lysosomes do?
- break down various molecules and worn out organelles
- can destroy disease causing organisms
- may break down material consumed by cell
What are vacuoles?
large vesicles made in the ER and golgi apparatus
What do vacuoles do?
- store food particles
- maintain water levels and ion concentrations
- store various organic compoundsd (e.g., proteins, toxins, pigments)
What is the central vacuole?
large vacuole in plant cells
What does the central vacuole do?
- maintain turgor pressure; influences cell rigidity
- plays roles in growth, storage, and sequestriation of toxic substances
What is the mitochondria?
the site of cellular respiration; energy factory of the cell
What does the mitochondria do?
makes ATP by breaking down glucose
What are chloroplasts?
the site of photosynthesis
What do chloroplasts do?
- convert sunlight into chemical energy
- produce glucose and oxygen
What does the cytoskeleton do?
provides a structureal framework for a cell
What are flagella?
long, hairlike structures extending from the cell membrane
What does the flagella do?
aid in cell movement
What are cillia?
short, hairlike structures (often numerous)
What do cillia do?
- aid in cell movement
- move substances along the cell’s surface
What kind of cells have a cell wall?
Plant cells; prokaryotes, some protists, and fungi
What does the cell wall do?
- protect the plant cell
- maintains shape
- prevents excess uptake of water
What do cell junctions do?
aid in interaction and communication between cells via physical contact
