Study Guide: Test #2-Review, Tools, Microscope, Cell, Cell Transport

Name:______Date:______

A. Review Test #1- Study Guide

B. Tools used by Scientists

ü Compound microscope- used in high school lab.

Magnifies 400-2000X.

i. Resolution- how well it distinguishes

between two points that are very close to one another.

ü Stereoscopic dissecting microscope- used during dissections and to see small organisms’ behavior (such as fruit fly or hydra). It magnifies only 10-50X. Uses reflected light

ü Electron Microscope- magnifies 250,000X. only dead specimens may be studied. It has revolutionized our understanding of cell ORGANELLES. Viruses can only be seen under this microscope

ü Ultracentrifuge- centrifuge that separates materials according to their density. It is like a salad spinner. It is used to collect large amounts of mitochondrial membranes, or cell membranes or ribosomes and their chemicals (also used to separate blood)

ü Microdissection apparatus- instruments used to perform microsurgery. Individual cell nuclei can be removed from cells and transferred to other cells. Often used during cloning.

ü Chromatography- technique that separates materials by taking advantage of their solubility. Often used to separate the pigments in chlorophyll.

ü Gel electrophoresis- procedure that uses electrical voltage to separate fragments of DNA. It is used during DNA fingerprinting which identifices people according to their DNA pattern. Used to solve crimes, paternity suits, identify soldiers who have died in wars.

ü Cell culturing- growing cells outside of the body in nutrient solutions. Cancer cells and other cells can be kept alive. They can be used to test the effectiveness of drugs. Pollutants can be studied on these cultured cells to see their impact on human cells.

C. Cell Theory

ü The basic unit of structure and function in all living things is the cell.

ü All living things are made of at least one cell.

ü All cells come from previously existing cells.

i. Exceptions

1. Where did the first cell come from?

2. Where do viruses fit in? They are not cells.

3. Mitochondria and Chloroplasts have their own DNA and can reproduce themselves.

D. Organization of Living Things

ü Molecules → Organelles → Cell* → Tissue → Organ → System → Organism → Population (species in an area) → Community (populations in an area) → Ecosystem (biotic (living) and abiotic (nonliving) interactions in an area) → Biosphere (Life on Earth)

E. Cells

ü Prokaryotes- cells that do not have a true nucleus. DNA floats in the cytoplasm. Do not have true organelles, only primitive ribosomes, cytoplasm, and a cell membrane. Evolved 3.8 billion years ago (living prokaryotes today- bacteria).

ü Eukaryotes- cells with a true nucleus and true organelles. DNA in the nucleus. Plants and animals

F. Structure determines Function

ü Cells specialize to have a structure that helps them perform a specific function

ü Cells of an individual organism have the SAME DNA; they may turn on/off certain genes on the DNA to become specialized to perform their function.

i. Ex.

1. Red Blood cells- small, round and no nucleus so they can carry oxygen through tiny capillaries

2. Fact cells- can enlarge and fill with fat so that this molecule can store food and therefore energy for the long term.

3. Nerve cells- contain many branching cell processes that allow nerve cells to communicate with one another and therefore respond to changes in the environment.

4. Muscle cells- are able to change their lengths thereby enabling organs to move. Smooth muscle moves food along the digestive tract.

G. Cell Organelles

ü Membrane- controls what enters/exits the cell. Selectively permeable. Made up of Proteins and Lipids. Called a “fluid mosaic” model

ü Nucleus- contains DNA (Chromatin → Chromosomes) that controls for the production of all cell proteins, controlling all aspects of cell’s activity

ü Nucleolus- produces RNA (ribosomes)

ü Endoplasmic Reticulum- channel passageways for materials moving through the cell (Smooth- without ribosomes; Rough-with ribosomes)

ü Golgi Body (apparatus)- packages materials that will be released by the cell

ü Vacuole- vesicles for storage of materials Plants- large vacuoles; Animals-smaller vacuoles

ü Lysosomes- break down old, worn out cell parts

ü Centrioles- animals only- rod shaped that aid in cell division

ü Mitochondria- powerhouse (Cellular respiration- Release energy (ATP) from food)

ü Chloroplasts- plants only- site of photosynthesis- using CO2, H2O, and light energy from the sun to form O2 and food (glucose)

ü Cell wall- plants only- give cell strength and rigidity. Contain cellulose (a fiber that you don’t digest but that helps you digest other foods)

ü Cytoplasm- watery environment on the inside of cell

ü Cytoskeleton- microtubules and microfilaments that give the cytoplasm some support

Differences between plant and animal cells: PLANTS ANIMALS

H. Using the Microscope

ü Know the parts of the microscope

ü Our microscopes-

Scan= 4X Low Power=10X High Power= 40X

Total Magnification = ocular lens x objective lens

ü Field of view decreases with increased magnification

ü The greater the magnification, the less light that goes through the specimen and reaches your eye.

ü Resolution is the ability of the microscope to distinguish between two separate points that are very close. It separates the points that even the human eye can’t see

ü Always center the specimen when changing from low to high power to keep the specimen in the middle of your field so you can see it in high power which has a much smaller field diameter.

ü Objects under the microscope appear upside down and backwards (so when you are moving a slide, remember you move left= specimen moves right; you move right= specimen moves left; you move up= specimen moves down; you move down = specimen moves up)

I. Making Connections

ü Pulse rate is measured per minute. It tells the number of times a person’s heart is beating/minute.

ü Pulse rate changes as activity level changes.

ü Most experiments measure a person’s resting pulse rate (control)

ü This lab discussed muscle fatigue which is the accumulation of Lactic Acid (waste) in muscles when engaging in exercise.

ü Experiment – Resting or Exercising vs the # of times that students could squeeze a clothespin

i. Independent Variable – X axis- Exercise

ii. Dependent Variable – Y axis - # of squeezes

J. Transport

ü Passive Transport = requires no energy

i. Examples: Diffusion and Osmosis

1. High → Low (with

concentration gradient)

ü Active Transport = requires ATP (energy)

i. Pinocytosis

ii. Phagocytosis

iii. Active Transport

1. Low → High (against

concentration gradient)

ü Cells in Solution

i. Hypotonic solution:

1. Ex. distilled water

2. More solute inside cell, more

water outside cell

a. Animal cell- swell

and burst

b. Plant cell- Turgid (don’t

burst because of cell wall)

ii. Isotonic Solution:

1. Same inside and out

a. Cells maintain dynamic equilibrium- no change

iii. Hypertonic Solution:

1. More solute outside cell, more water inside cell

a. Cell will shrivel

A. Label the organelles in the following cells. B. Identify whether they are a prokaryote or a eukaryote. C. Identify whether they are an animal or a plant cell.

What organelle is represented in the picture to the right?

Label structures A and B.

Label the following parts of the microscope.

Explain why:______

*Show what will happen over time. Describe why this occurs.