AP Chapter 3 - Cells

who discovered cells?

Robert Hooke

How did cells get discovered?

looked at cork under microscope

cell theory

cells are the building block of life, all cells come from preexisting cells, cells are the smallest unit of life that has all life properties, each cell maintains homeostasis

characteristics of life

homeostasis, reproduction, growth, respond to environment, evolution, utilizes energy

2 types of cells

unicellular, multicellular

prokaryotic

no nucleus

eukaryotic

nucleus

similarities between eukaryotes and prokaryotes

DNA, riboses, cytoplasm, plasma membrane, both can be unicellular

prokaryotic differences

~3.5 billion years old, smaller, less structurally complex, no membrane bound organelles, divide by binary fission, bacteria and archaea

eukaryotic differences

evolved from prokaryotic ~2.1 billion years ago, 10-100x larger, more structurally complex, can be multicellular, many membrane bound organelles, divide by mitosis, plants/animals/fungi/protists

what governs the size of cells?

the total metabolic activities of the cell are proportional to the volume of it’s cytoplasm, as cell increase in size the volume of the cytoplasm increases faster than the surface area (making it difficult for enough energy to cross the membrane)

what microscopes can be used to visualize cells?

light, transmission, scanning electron

light microscope

light passes through sample, lens to magnify, magnify up to 1000x (enough to see bacteria)

transmission microscope

electrons bombard thin slice of sample and some pass through, detected with detect electrons and generate a 2D image. can magnify up to 100,000x (can see cellular details)

scanning electron microscope

electrons are used to scan the surface of a sample, produces 3D image

membrane bound organelles

compartmentalize chemical reactions

organelles involved in protein synthesis

nucleus, RER, ribosomes, golgi apparatus, vesicles

factory for lipids and carbs

SER

nucleus function

houses and protects most of the cells DNA

dna purpose

holds the instructions on how to make each protein

DNA function

controls structure and behavior of cell

DNA is packed into ____

chromosomes

how many chromosomes do humans have

46

where is the nucleolus

in middle of nucleus

nucleolus function

make ribosomal RNA

what makes the ribosome

rRNA and protein

what does a ribosome do

synthesis of proteins

nuclear envelope structure

double layer membrane with nuclear pores (“doorways”)

gene

small segment of dna

where are the instructions to make a protein found?

gene

Nucleus role in protein synthesis

convert DNA to mRNA via transcription to carry the instructions into the cytoplasm

ribosome structure

two subunits (large and small), non membraneous

ribosome function

grabs and reads the mRNA instructions to make a protein vis translation

endoplasmic reticulum types

rough, smooth

RER structure

flattened sheets, ribosomes

SER structure

hollow tubes

RER function

protein factory

SER function

carb and lipid factory, Calcium ion storage

golgi apparatus structure

stack of flattened disks, connected via vesicular transport

golgi function

modifies, stores, and distributes proteins. makes lysosomes

vesicle structure

small bubble of membrane

vesicle function

ships and store cellular products

2 types of specialized vesicles

lysosome, peroxisome

peroxisome function

collects toxins and destroys

lysosome function

recycles worn-out organelles/food and send out the remaining product via exocytosis

mitochondria structure

outer membrane, intermembrane, intermembrane space, matrix

matrix

center of inter membrane space

mitochondria function

cellular respiration

cellular respiration

use glucose and other biological molecules to make ATP

organelle involved in support and movement

flagella, cilia, cytoskeleton, centrioles, extracellular matrix

where are flagella and cilia found

plants, animals, fungi, protista

cilia structure

short cellular extensions found in groups, bristle-like

cilia function

move in coordinated sweeping motion to move substances across the surface of the cell

flagella structure

long tail-like cellular extentions

flagella function

moves in propeller like motion to move the cell forward

only cell in humans with flagella

sperm

centrioles structure

short, rode-like structures near the nucleus

centrioles function

cell division, help align and divide genetic material

cytoskeleton structure

located inside cell, network of protein fibers, easily disassembled and reassembled

cytoskeleton function

maintain cell shape, anchors organelles in place, intracellular highways

function of plasma membrane is similar in function to our ______

skin

plasma membrane function

barrier between external and internal environment, sensitivity to the environment, regulates the transport of material into and out of the cell, maintain stable internal environment

plasma membrane structure

phospholipid bilayer, cholesterol, studded with membrane proteins, fluid mosaic

fluid mosaic

proteins can move through the bilayer

phospholipid structure

hydrophilic head, hydrophobic tail

cholesterol function

increases flexibility of the plasma membrane, helps anchor proteins to the plasma membrane

membrane proteins functions

anchoring, identifiers, enzymes, receptors, carrier proteins, channels

types of membrane transport

passive and active

types of passive transport

diffusion through lipid layer, diffusion through channels, osmosis, facilitated diffusion

what types of molecules use diffusion through lipid layer

small, uncharged, lipid-soluble

what types of molecules use diffusion through channels

large, charged, water-soluble proteins

what types of molecules use facilitated diffusion

large, charged, water soluble proteins

what is facilitated diffusion

diffusion across membrane with the aid of a transport protein (similar to a doorway)

what types of molecules use osmosis

water

what is osmosis

net movement of H2O across a selectively permeable membrane with the aid of a protein (because water has partial charges)

when does osmosis occur?

when there’s a membrane that doesn’t allow some solutes through so water will move instead to reach equilibrium

types of tonicity

hyper, hypo, iso

hypertonic

cell place in a more concentrated solution

hypertonic result

water leaves cell, membrane shrinks

hypotonic

cell placed in less concentrated solution

hypotonic result

water enters cell, cell expands and can lyse

isotonic

cell placed in equal concentration solution

isotonic result

no net change

types of active transport

vesicular, pumps

types of vesicular transport

exocytosis, endocytosis

pumps

proteins that have receptor cites for substances

sodium potassium pump

very important for a lot of life functions

how does the sodium potassium pump work?

3 sodium ions and ATP bind to pump, pump changes shape and allows Na through. new shape allows potassium ions to bind. releasing the phosphate group allows the channel to revert to original form and release the potassium

endocytosis

brings substances into the cell

exocytosis

moves substances out of the cell