Cell study guide

Miller-Urey experiment

A scientific experiment that simulated early Earth conditions to test the origins of life. It demonstrated that organic compounds could be made from inorganic precursors under conditions thought to resemble those of the early Earth.

timeline

earth forms, early atmosphere forms, first amino acids and nucleotides form, DNA and RNA form, first anaerobic prokaryotic living cells form, bacteria produces oxygen in earth’s atmosphere through photosynthesis, bacteria begin to become aerobic, eukaryotic cells arise, the first multicellular organisms form, sexual reproduction, Cambrian explosion and Paleozoic era, mesozoic era, Cenozoic era

theory of endosymbiosis

Eukaryotic cells evolved when large prokaryotic cells engulfed smaller, independent bacteria which lived inside the host and evolved into specialized organelles.

evidence of endosymbiosis

organelles contain their own DNA, have double membranes, divide via binary fission, and have ribosomes similar to modern bacteria

cell membrane

found in prokaryotes, plants, and animals. flexible boundary that surrounds the cell. made of a bi-layer of proteins 7 lipids. separates the cell from outside environment. selectively permeable

cell wall

found in prokaryotes and plants. rigid structure outside plasma membrane, made of cellulose. provides additional support and protection, giving cell its shape.

nucleus

found in animal and plants. contains DNA and controls cell activities

nuclear membrane/envelope

found in plants and animals. double membrane layer with thousands of pores that surrounds nucleus. allows material such as RNA to move in and out of nucleus

nucleolus

found in animals and plants. spherical structure found in nucleus. synthesizes ribosomes

cytoplasm

found in prokaryotes, animals, and plants. clear jelly fluid inside the cell. chemical reactions take place here

cytoskeleton

found in prokaryotes, animals, and plants. network of protein filaments that helps the cell to maintain its shape and structure as well as helps with cell movement

cilia/flagella

found in animals and prokaryotes. microtubules that help move the cell. cilia move substances over the cell while flagella moves the cell itself

ribosome

found in prokaryotes, animals, and plants. tiny and abundant - made of RNA and protein. site of protein synthesis

endoplasmic reticulum

found in animals and plants. highly folded membrane in the cytoplasm. can be rough or smooth. site of protein synthesis

Golgi apparatus

found in animals and plants. flattened stack of tubular membrane - found near cell membrane. sorts & packs protein into vesicle and transports them

lysosome

found in animals. contains digestive enzymes and digests food, bacteria, and worn out organelle

peroxisome

found in animals and plants. contains catalase enzyme which breaks down toxic substances

vacuole

found in plants and some animals. it is a membrane bound sac that stores food, enzyme and other material and also provides support

vesicle

found in plants and animals and is a membrane bound sac that moves material into, out of and around the cell

mitochondrion

found in animals and plants. double membrane bound organelle that produces energy for growth, development, and movement

centrioles

found in animals. small structure outside nucleus formed from microtubules. helps in mitosis and forming flagella/cilia

chloroplast

found in plants. double membrane bound organelle that has pigment chlorophyll in inner. captures light and converts it to chemical energy (photosynthesis)

organelle that plants have

cell membrane, cell wall, nucleus, nuclear membrane/envelope, nucleolus, cytoplasm, cytoskeleton, ribosome, er, Golgi apparatus, peroxisome, vacuole, vesicle, mitochondrion, chloroplast

organelles that animals have

cell membrane, nucleus, nuclear membrane/envelope, nucleolus, cytoplasm, cytoskeleton, cilia/flagella, ribosome, er, Golgi apparatus, lysosome, peroxisome, vacuole (small or none), vesicle, mitochondrion, centrioles

organelles that prokaryotes have

cell membrane, cell wall, cytoplasm, cytoskeleton, cilia/flagella, ribosome

synthesizing proteins process

1. Nucleus (has instructions)

2. Ribosome (Makes hormones)

3. ER (transports and stores hormones, moves them to golgi apparatus)

4. Golgi (modifies hormones and makes them into 3D structures)

5. Secretory vesicle (releases contents to outside)

6. Cell membrane (exits the cell)

key components of cell membrane

phospholipid bilayer (polar hydrophilic heads, non polar hydrophobic tails), proteins, cholesterol, carbohydrates

phospholipids in cell membranes

semipermeable. generally, the smaller and less polar a molecule, the easier and faster it will diffuse across a cell membrane.

cholesterol in cell membranes

cholesterol is a lipid that makes the membrane less fluid and less permeable and it keeps the membrane stable at body temp

integral proteins

carrier molecules or channels. help transport substances that can not diffuse

peripheral proteins

either found on membrane surface or bound to an integral protein. act as receptors or cell recognition.

membrane proteins

determine membrane’s functions - peripheral proteins and integral proteins

carbohydrates in membranes

usually carbohydrate chains are attached to embedded glycoproteins. help with cell recognition (distinguishing one cell from another)

predicting how molecules will leave the cell

small non polar molecules cross easily. small uncharged polar molecules pass slowly. large uncharged polar molecules and charged ions require protein channels or active transport

hypertonic

higher solute concentration outside the cell, causing water to leave and cell to shrink

hypotonic

lower solute concentration, causing water to enter and cell to swell

isotonic

balance solute concentration inside and outside the cell

diffusion

passive process (requires no cellular energy). net movement of particles from an area of higher concentration to an area of lower concentration.

osmosis

passive process. movement of water across a semi permeable membrane from an area of lower solute concentration to an area of higher solute concentration, equalizing concentration on both sides.

facilitated diffusion

passive transport. uses integral proteins (channel or carrier) to diffuse substances

Active transport

active process. moves molecules against the natural diffusion direction (low concentration to high concentration) like a pump

endocytosis

active transport. Process of engulfing materials into a cell by membrane folding.

exocytosis

active transport. a vesicle loaded with molecules fuses with the cell membrane, opening up and spilling contents outside the cell

unique to plant cells

chloroplast

unique to animal cells

centrioles, lysosome