exploring cells

what is resolution

the ability of a microscope to distinguish two close objects as separate. higher resolution=more clarity and detail

What is the difference between magnification and resolution?

• magnification makes an object look bigger

• resolution allows you to see more detail

what limits resolution in a light microscope

the wavelength of light. longer wavelengths give lower resolution

why do electron microscopes have higher resolution

electrons have shorter wavelength than visible light, allowing more detail to be seen

what does a light microscope use

visible/white light that passes through the specimen

what is contrast

the visible difference between parts of the specimen that allows you to distinguish themwhy a

why are stains use in light microscopy

to increase contrast and make structures easier to see. staining often kills the cell

what is fluorescence microscopy used for

to detect specific proteins, nucleic acids, or other molecules by labeling them with fluorescence dyes/proteins

what does TEM stand for and what does it show

• transmission electron microscope

  • electrons pass through the specimen, allowing you to see internal structures

what does SEM stand for and what does it show

• scanning electron microscope

  • electrons scan the surface of a specimen, showing surface characteristics

what are the 3 main ideas of cell theory

1. all organisms are made of cells

2. the cell is the fundamental unit of life

   1. all new cells come from existing cells

what are the 4 things all cells have in common

1. plasma membrane

2. cytosol

3. DNA

4. ribosomes

why do cells generally stay small

small cells have higher surface area to volume ratio, allowing materials to move in and out more efficiently

what happens to the surface area to volume ratio as a cell gets bigger

it decreases

why is a lower SA:V ratio a problem

there is more volume to support but proportionally less surface area for exchanging materials

what does surface area allow a cell to do

exchange materials with its environment- bring in nutrients and remove waste.

what does plasma membrane do

it controls what enters and leaves the cell

what is the cytosol

the fluid inside the cell

what doe DNA do

contains cells genetic instructions

what do ribosomes do

make proteins

what are the 2 groups of prokaryotes

• bacteria

• archaea

what is the main feature of prokaryotic cells

they lack a nucleus and membrane-filled organelles

where is DNA located in a prokaryotic cell

in the nucleoid region

what are extremophiles

organisms that live in extreme environments; some archaea are extremophiles

where is the cell wall of a prokaryotic cell located

outside plasma membrane

what is function of cell wall of prokaryotic cell

provide support and shape

what does the plasma membrane of a prokaryotic cell do

control what enters and leaves the cell

what is the nucleoid

the region where the prokaryotic cells DNA is located

how is prokaryotic DNA different from eukaryotic DNA location

prokaryotic have no nucleus, so their DNA is not enclosed by a membrane

which type of cell has membrane-bound organelles

eukaryotic cells

which type of cell is generally smaller and simpler

prokaryotic cells

what organism are eukaryotic

animals, plants, fungi, & protist

how do prokaryotic and eukaryotic cells differ in complexity

• Prokaryotic cells are generally smaller and simpler

• Eukaryotic cells are generally larger and more complex

what is plasma membrane made of

a phospholipid bilayer (2 layers of phospholipid)

how are phospholipids arranged in the membrane

• hydrophilic heads face water

  • hydrophobic tails face inward

what does semipermeable mean

the membrane controls what enters and leaves the cell

what is an integral protein

a protein embedded in or spanning in the membrane

what is a peripheral protein

a protein attached to one side of the membrane

where is the cytoplasm located in a eukaryotic cell

inside the plasma membrane but outside the nucleus

what is main function of the nucleus

stores more of the cell’s DNA

what are nuclear pores

openings that allow materials to enter and leave the nucleus wh

what is the difference between chromatin and chromosomes

• chromatin= loose DNA

• chromosomes= condensed DNA

what does the nucleolus do

make ribosome components

what is nucleoplasm

the gel-like material inside the nucleus

what is nuclear envelope

a double membrane surrounding the nucleus

what is function of nuclear envelope

separates and protects the DNA from cytoplasm

what are nuclear pores

openings in the nuclear envelope that control what enters and leaves the nucleus

where does transcription occur

Nucleus- DNA → RNA

what does translation occur

cytoplasm- RNA → Protein

where is nucleolus located

inside the nucleus

what is the main function of the nucleolus

assembles ribosomes

what is the nucleolus made up/uses to assemble ribsomes

rRNA and proteins

what do ribosomes make?

proteins

what are the 2 subunits of a ribosome

Large and small subunits

what do ribosomes read to make a protein

rRNAwh

where can ribosomes be found

• free in the cytosol

  • attached to the ER

what is the endomembrane system

cell structures that work together to make, modify, package, and transport proteins/lipids

what does the rough ER mainly help make

proteins

what does the golgi do

modifies, sorts, and packages proteins and lipids

what do vesicles do

transport materials around the cell

what do lysosomes do

break down and recycle materials wha

what is the basic protein pathway through the endomembrane system

rough ER → vesicle → Golgi → vesicle → destination

what is the ER

a network of connected sacs and tubules that help make and move material

what is the lumen

the hollow/internal space inside the ER

what makes the rough ER “rough”

ribosomes attached to its surface

what does rough er mainly make

proteins

what does smooth er mainly make

lipids

how is the ER related to the nuclear envelope

the ER is continuous with the nuclear envelope

functions of smooth er

• make lipids

• help with carbohydrate metabolism

• detoxifies harmful substances

• stores calcium

why is smooth er important in liver cells

helps detoxify drugs and harmful substances

what does smooth er store

calcium ions (ca²+)

does smooth er have a lot or little to no ribosomes

little to none

what happens to proteins after ribosomes make them on the rough er

they enter the er lumen and are processed/modified wh

where can rough er proteins go after processing

to the golgi, cell membrane, or outside cell

what does the rough er make besides proteins

phospholipids for cell membranes

what is the cis face of the golgi

the receiving/incoming side that faces the ER

what is the trans face of the golgi

the leaving/outgoing side where materials are packaged into vesicles

what do lysosomes contain

hydrolytic enzymes (break things down with water)

what is the main function of peroxisomes

break down fatty acids/ amino acids and help detoxify harmful substances

what harmful substances can peroxisomes produce

h2o2 (hydrogen peroxide)

how do peroxisomes deal with h2o2

they contain enzymes that break it down

how many membranes surround a peroxisome

one membrane

what are vacuoles

large membrane-bound sacs used for storage and other maintenance functions

where are vacuoles derived from

the ER and golgi

what is the function of a food vacuole

holds and help digest food

what is this main function for cholorplast

they capture sunlight energy and store it as chemical energy in carbs

what is the main function of mitochondria

they convert energy from carbohydrates into usable ATP

where are chloroplasts found

plants and algae

where are mitochondria found

plants and animals

what is atp

usable energy for the cell

what is the endosymbiotic theory

the theory that mitochondria and chloroplasts were once independent organisms/bacteria that became parts in larger cells

what evidence supports the endosymbiotic theory

they have double membrane, their own ribosomes, circular DNA, and can reproduce somewhat independently

what type of of DNA do mitochondria and chloroplasts have

circular DNA

how many membranes does a mitochondrion have

two, and outer and inner membrane

what are cristae

folds of inner mitochondrial membrane

why does the inner membrane have folds

to increase surface area for atp production processes

what is the mitochondrial matrix

the space enclosed by the inner membrane

what is the main function of chloroplasts

they are the site of photosynthesis and capture light energy to make chemical energy

where are chloroplasts found

plants and algae