Biology - Microscopes and Cells Quiz Flashcards
what do microscopes do
magnify objects and make small things appear larger
what is the main benefit of a microscope
resolution
whats resolution
the ability to see fine detail
whats a compound microscope
microscope with 2 or more lenses
what is the most common type of microscope
compound
what do you use a compound microscope for
to look at transparent specimens
what is the max magnification of a compound microscope
1000x
how does a compound microscope produce an image
passes light through the specimen
what’s the structure of a compound microscope
1 eyepiece and 3 objective lenses
what is a dissecting microscope used for
to look at solid objects
whats the max magnification on a dissecting microscope
85x
what’s the structure of a dissecting microscope
2 eyepieces and 2 light sources
what are the advantages of a dissecting microscope
images are produced in colour and 3-d/liign material can be used
what are the disadvantages of a dissecting microscope
low magnification and poor resolution at high magnifications as the light rays are bent
what is transmitted light
light passing through a specimen
whats incident light
light reflecting off a specimen
whats parfocal
concept that when the microscope is focused on one power it should still be in focus when switched to another power
whats an inverted image
when the microscope shows it upside down and backwards
whats a virtual image
when it shows the same as it really is
what are the two meanings of magnification
- the number of times a microscope enlarges the specimen
- the number of times bigger a diagram is when compared to the actual size of a specimen
what is field of view
the diameter of what you see
what happens if something is on low magnification in relation to its field of view
you will see more around the object than if it was on high magnification
what is the fit number
an estimate of the number of times an object can be placed across the diameter
what is scale used for
to compare the diagram size with the actual size of the specimen
what did the use of stains or colouring agents show
that particular stains attached to particular parts of the cell which improved the contrast between internal structures and produced better images
what is the disadvantage of staining techniques
it kills the cells, making it not possible to view living tissue with this technique
whats resolving power
the ability to distinguish between two structures that are very close together
how does an electron microscope work
uses a beam of electrons instead of a light wave and is able to produce images that provide fine detail
how does the transmission electron microscope work
depends on a beam of electrons passed through very thin section of fixed and stained tissue imbedded in plastic
what did the microscope make possible
the obtaining of evidence for or against generally accepted opinions or theories about living things
whats spontaneous generation
the idea that life could emerge spontaneously from non-living matter
what does the occular lense do
magnify specimen
funciton of fine focus
makes tiny adjustments to focus specimen
revolving nose peice function
urns objective lense power
diaphragm fucniton
adjust the amount of light
base function
supports and stabilizes
hinge function
changes the angle
function of stage clips
hold the slide in place
arm function
support of microscope
objective lens function
3 different lenses that magnify the object at different rates
course focus funciton
allows you to focus by moving the lens closer or farther from the stage
whats the stage
the place you rest the slide on
what does the light do
illuminate the object
how do you carry a microscope
with one hand on the arm and one hand on the base
how do you focus a microscope
using the lowest magnification lens and the course focus knob
how do you know which one is the course focus knob
it is the bigger know that is above the other dial
what are lenses used for
magnification
how do light microscopes work
a beam of light is directed through a specimen
what can you view with the resolution of a light microscope
plant/animal cells and most bacteria but not sub-cellular structure or viruses
how many micrometres are in one millimetre
1000
how do you get total magnification
multiply the power of both lenses being used together
what’s the formula to calculate field of view
higher magnification/lower magnification = lower power/higher power
what is the formula for estimating cell size
actual size = field diameter/fit number
how did microscopes lead to the development of cell theory
allowed observations to be made by several scientists regarding cell structure because they could see very small details and patterns in tiny objects
describe the work of Louis Pasteur in refuting the theory of spontaneous generation
he added an s-shaped curve into the neck of some of the flasks within Spallanzani’s previous experiment in order to control what went into the flask as only air could pass through but any particles would get stuck
what is meant by control in an experiment
keeping things the same so that you are only measuring one thing
who was the first to question spontaneous generation and in what year
Francisco Redi in 1668
what did Pasteur’s experiment show
that spontaneous generation did not occur and that microorganism are found in the air
when was the importance of the cell as the functional unit of life recognized
the 1830s
what are the three components of cell theory
- all living things are made up of one or more cells
- all life functions take place in cells making them the smallest unit of life
- all cells are produced from pre-existing cells through the process of cell division
what does cell theory apply to
all living things
why are viruses or prions not considered cells
because they fall into a category that is neither living nor non-living even though they may exhibit characteristics of living cells due to how they don’t become active until they get into a cell
what is an open system
one that must interact with its environment to maintain its existence
how do cells function efficiently
by interacting with their environment and each other
what are the components of the cell called
organelles
what does the functioning of organelles do
maintain the life processes of the cell
how do cells maintain the life process
within specialized structures called organelles that each have their own function to perform
what are some of the life processes cells perform
intake of nutrients, movement, growth, response to stimuli, exchange of gases, waste removal, reproduction
whats the cell membrane
a protective barrier that allows for the transport of materials in and out of the cell
whats the cytoplasm
a gel-like substance inside the cell membrane that contains nutrients, allows for movement and suspends the organelles
whats the mitochondria
rod-like structures where cellular respiration occurs
whats the mitochondria referred to
the powerhouse of the cell
whats cellular respiration
where chemical energy in sugars is converted to energy that can be used by the cell
whats the nuclear envelope
double membrane that surrounds the cell and regulates the passage of macromolecules through multiple pores
whats the nucleus
organelle that contains the genetic material of the cell and directs all cellular activities
whats the nucleolus
structure made up of proteins and RNA that rewrites rRNA and combines it with proteins
whats smooth endoplasmic reticulum
series of tubes extending from the nuclear envelope associated with lipid production
whats rough endoplasmic reticulum
series of tubes extending from the nuclear envelope associated with protein synthesis
whats the Golgi apparatus
flat dis shaped sacs involved in transporting substances from the endoplasmic reticulum out of the cell
whats the vacuole
organelle bounded by a membrane that stores nutrients, products of secretion, fats and water
what are lysosomes
sacs within the cell that contain strong chemicals that digest molecules
what are ribosomes
granules where proteins are produced
what are centrioles
a small set of 2 microtubules found in animal cells that move towards opposite ends of the nucleus when it is time for cell division
whats the cell wall
rigid frame around the cell that provides strength and support to plant cells
what are chloroplasts
organelles that contain chlorophyll which produces a green colour and are the site of photosynthesis; they are only found in plant cells
what is cytosol
the fluid part of the cytoplasm where the organelles are suspended from
what makes up the cytoplasm
cytosol and organelles
what are the major gas elements within plant and animal cells
carbon, hydrogen, oxygen and nitrogen
what are the major elements of cell structure organized into
four major organic compounds
what are the four major organic compounds within a cell
lipids, carbohydrates, starches and cellulose
what is the other major compound found in all plant and animal cells
water
what does water do within a cell
its the solvent that provides the environment for all biological reactions inside and outside cells
what are trace substances
other substances present in tiny amounts that are essential for the health of the cell
what are the 4 major trace elements in a cell
magnesium, zinc, manganese and iron
what are 3 similarities between plant and animal cells
- both have a cell membrane
- both have a cytoskeleton
- both have DNA
whats a cytoskeleton
internal network of fibres made up of proteins and lipids
what is DNA
genetic material made up of sugars, nitrogen basis and phosphate
what are 5 differences between plant and animal cells
- animal cells have centrioles
- animal cells have lysosomes
- plants have a cell wall
- plants have chlorophyll which makes photosynthesis possible
- plant cells have a large central vacuole whereas animal cells have a much smaller vacuole
what do all cells contain no matter their type
cell membrane, cytoplasm, chromosomes and ribosomes
whats a prokaryotic cell
very small cells that do not have a nucleus or nuclear membrane or membrane-bound organelles but have a nucleoid region
what are eukaryotic cells
cells with a nucleus and a nuclear membrane that are generally larger than prokaryotic cells
