USABO and AP Biology Unit 2 or Chapters 6 and 7 Flashcards Extremely Detailed

Contains terms from both, (Both) means that this flashcard is important for both things, and (USABO only) means just for USABO it is not necessary for AP Bio.

When was microscopy invented? (Both)

1590s and refined in the 1600s

Who discovered living cells (USABO only)

Anton van Leeuwenhoek

Definition of Light Microscope and it’s abbreviation (Both)

LM and they are microscopes where visible light is passed through a specimen and then through glass lenses

What three important parameters exist for microscopes (Both)

Magnification, resolution, and contrast

What is the smallest size a LM can see? (USABO only)

200 nanometers

What type of microscope parameter stops LMs from viewing things as small as electron microscopes? (Both)

Resolution

How does an electron microscope work and what is it’s abbreviation? (Both)

Uses beams of electrons through a specimen, EM

Why are electron microscopes better at viewing smaller objects? (Both)

They have shorter wavelengths then light

Use of Scanning Electron Microscopes and abbreviation (Both)

Useful for detailed topography of an organism, SEM

How do SEM’s work (Both)

The organism is plated in a thin film of gold, which excites the electrons on the gold, creating a 3D electrical image on the screen of a surface

How do Transmission Electron Microscopes work and what’s their abbreviation?

An electron beam is aimed through a thin section of a specimen, which has been stained by heavy metals that attach to certain structures in the cell, enhancing the electron density and making them more visible. (Like dying a cell with heavy metals). Abbreviation is TEM

What are the pros of light microscopy, 2 main ones (Both)

1. Light microscopy is easier to use, less expensive, and more common

2. Light microscopy can be used to study living cells

What is/are the con(s) of light microscopy? (Both)

It is harder or impossible to see subcellular structures

Pros of electron microscopes (Both)

1. Can see 100 times more zoomed in then a light microscope

Cons of EM (Both)

The preparations used to prepare the specimen usually kill it, so you can’t view live cells

Every type of light microscopy (USABO only, super important please memorize if you’re in USABO)

1. Brightfield

2. Phase contrast

3. Different Interference Contrast (Nomarski)

4. Fluorescence

5. Confocal

6. Deconvolution

7. Super resolution

8. Cryo-electron microscopy

How does brightfield light microscopy work? (USABO only)

Light passes through the specimen, and you get contrast without dyes, but the specimen has to be killed or preserved

How does phase contrast light microscopy work? (USABO only)

Variations in the density are amplified to enhance contrast without dyes, and is useful for examining living cells

How does difference interference contrast light microscopy work? (USABO only)

Optical illusions are used to exaggerate density, resulting to 3D like images, and can be used on living organisms

How does fluorescence light microscopy work? (USABO only)

Locations of specific molecules are revealed by labeling molecules with dyes and UV light, but the final image is blurry but magnified much higher. You have to kill/preserve the cell

How does confocal microscopy work? (USABO only)

A laser which is used to create a single plane of microscopy in fluorescence, a 3D image is now created by adding different planes. Usually still blurry and the specimen has to die

How does deconvolution microscopy work? (USABO only)

A deconvolution software that removes and reassigns light, creating a sharper image. Basically uses fluorescence microscopy and focuses it in. Increases resolution

How does super-resolution microscopy work? (USABO only)

Uses individual UV light pieces to excite fluorescent molecules. The positions are rounded and the changing images create a more resolved image, which can be increadly small, up to 10-20 nm across.

What temperature are the specimens in cryo electron microscopy frozen at? (USABO only)

At least -160 degrees celsius

Use and how you use cryo-electron microscopy? (USABO only)

It is used to view detailed protein structures and makes an image of tiny electron graphs

Definition of Cell Fractionation (Both)

A technique for studying cell structure by taking apart cells and separating major organelles from each other

Steps of Cell Fractionation (Both)

Homogenization, centrifugation, differential centrifugation

Definition of centrifugation (Both)

A high speed rotational force that pulls things away from each other, essentially separating them

Definition of homogenization in the cell Fractionation context (Both)

Mixing up stuff in a blender and making them into a homogenous mixture

What is the following thing called after homogenization? (Both)

Homogenate

Definition of Differential Centrifugation and why we do it(both)

When substances are put into a centrifuge and it spins at different speeds. When a centrifuge works, it’s forces are measured in gs, so a different type of cell organelle or part appears at the bottom of the tube for each g. For example 1000gs shows nuclei and cellular debris.

Two types of cells (Both)

Prokaryotic and Eukaryotic

Similar features for both types of cells (Both)

1. Bound by a plasma or cell membrane

2. They have cytosol

3. All cells have chromosomes

4. All cells have ribosomes

Definition of cytosol (Both)

A jelly like fluid where all cells are suspended in

Differences between eukaryotes and prokaryotes (Both)

1. Eukaryotic cells have membrane bound organelles, meaning each organelle has a membrane that separates it

2. Prokaryotic cells don’t have membrane bound organelles

3. Eukaryotic chromosomes are stored in the nucleus

4. Prokaryotic cells don’t have a nucleus, they have a nucleoid which is a concentrated region of DNA in a membrane

5. Eukaryotes are generally much larger than prokaryotes

Definition of cytoplasm, and which cell has it?

the area between the nucleus and the plasma membrane in a cell, and both have it. For prokaryotes it’s the entire cell

Fill in the blank, for each square micrometer of a membrane, only a __________________________________________________________ (Both)

limited amount of a particular substance can cross per second

The ratio between what two mathematical terms is essential to cell biology? (Both)

Ratio of surface area to volume

What mathematical law support this claim and state the law you can state a close version as long as you understand it? There are two parts to this law (USABO only)

1. Area is proportional to a linear dimension squared whereas volume is proportional to the linear dimension cubed

2. As an object increases in size, the ratio of it’s surface area decreases proportionately

Square Cube Law

How does the Square Cube Law affect life? (three things) (Both)

1. Smaller cells have larger surface area

2. Usually the larger a cell gets the longer it gets with it

3. Limits cell size, and supports why large organisms usually don’t have larger cells, just more similar sized cells

Main Purpose of the Nucleus (Both)

Contains most of the genes in the eukaryotic cell

What other organelles contain DNA in eukaryotes? (Both)

Mitochondria and Chloroplasts

Role of the nuclear envelope (Both)

Encloses the Nucleus, separating it’s contents from the cytoplasm

What type of membrane encloses the Nucleus? (Both)

Double membrane

How big is the space between the double membrane in the nucleus? (USABO only)

20nm - 40nm

What perforates the nuclear envelope? (Both)

Pores

Definition of a pore complex (Both)

An intricate protein structure that lines each pore and plays an important role in the cell by regulating enter and exit of proteins and RNA

Where is the Nuclear Lamina (Both)

Lines the nuclear envelope everywhere except the pore

What is the Nuclear Lamina made of and what does it do? (Both)

It is made of proteins and it maintains the Nuclear lining

Nuclear Matrix what is it tell everything about it(USABO only)

Nuclear matrix is a concept that has evidence from some scientists that may help the lamina and envelope function effectively together

Definition of a Chromosome

Discrete units that carry genetic information shaped kind of like an X

What protein does DNA wrap around in chromosomes

Histones