chapter 6: cells

Question 1

why are cells small?

Answer 1

cells want to maximize their SA so they want a smaller size to maintain its volume

Question 2

Light microscopy (LM)

Answer 2

visible light passes through a specimens that goes through glass lenses and bends the light so the image gets magnified
ALIVE cells

Question 3

magnify

Answer 3

increases the image however if u increase magnification without resolution the image is blurry

Question 4

resolution

Answer 4

the clearness of a photo

Question 5

types of LM

Answer 5

contrast:
used on cells that have no color and are in liquids like water that are also colorless. uses a stain/dye to distinguish but this can be toxic to cells.
photo-contrast:
a better option as it creates an image of the cells using wavelengths of light coming in and out of the cells
fluorescence:
molecule is excited by high energy and gets absorbed by electrons but then released in lower energy state. this lacks magnification but has the colors to distinguish

Question 6

electron microscopy (EM)

Answer 6

LM lacks resolution especially in smaller cells so EM utilizes electron beams with small wavelengths allowing more magnification and resolution
KILLS cells and only works with already dead ones

Question 7

types of EM

Answer 7

scanning em:
focus a beam on electrons on the surface and creates a 3D model via plating
transmission em:
focus beam of electrons through thin sections of the cells which sliced and looks internally

Question 8

cell fractionation + differential centrifugation

Answer 8

takes cells apart and separated by size
and separates components by leaving behind pellets (more pellets mean larger molecule)

Question 9

plasma membrane

Answer 9

acts as selective barrier and regulates cell chemical composition (EM needed) and is a phospholipid bilayer

Question 10

nucleus

Answer 10

protects dna
controls cell
double membrane
command center
genome lives here

Question 11

nucleolus

Answer 11

region that is active in synthesis of rRNA

Question 12

nuclear envelope

Answer 12

double membrane that encloses nucleus and separates it from cytoplasm

Question 13

chromatin

Answer 13

complex of DNA and protein that makes up the chromosome

Question 14

nuclear lamina

Answer 14

nuclear side of envelope that has protein filaments maintains shape of nucleus

Question 15

nuclear pore complex

Answer 15

multi-protein that forms channels allowing selected molecules to move in

Question 16

ribosome

Answer 16

composed of rRNA and synthesizes proteins