Unit 1 Flashcards
What is a cell?
Considered to be the basic unit of structure and function and the smallest independent unit capable of displaying the characteristics of life
What are the levels of organization in bio?
Atoms>molecules>cells>tissue> organ>systems>organism>populations>communities>ecosystems>biosphere
Characteristics of living things
- are made up of cells
- reproduce on their own
- grow
- obtain and use energy
- undergo metabolism
- maintain homeostasis
- respond to stimuli
- adapt to their environment
What is homeostasis?
Maintaining a constant internal environment
Ex) too hot-hyperthermia
too cold-hypothermia
What are the four points of The Cell Theory?
- all living organisms are composed of one or more cells
- cells are the basic unit of structure and function in all organisms
- all cells are derived from pre existing cells
- in a multi cellular organism, the function of the entire organism depends on the total activity of its independent cells
What is Biogenisis?
The idea that life arises from life
What are the three basic components of a cell?
- plasma membrane
- region containing DNA
- cytoplasm
Describe Prokaryotic Cells
- they have no nucleus (nuclear region not separated from the cytoplasm by a membrane)
- lacks membrane bound organelles
What are the three types of prokaryotic cells?
1) Eubacteria (true bacteria that makes zits and sore throats)
2) Cyanobacteria (blue and green bacteria found in lichens)
3) Archaebacteria (ancient newly discovered bacteria that can survive extreme conditions)
What are Eukaryotic cells?
- cells with a present nucleus
- separated by a membrane from the cytoplasm
- contain internal membranes and organelles
- all higher life forms (all kingdoms except Eubacteria and archeae)
Who id francesco redi?
Did the first controlled experiment
Hypothesized that maggots cannot appear in meat if flies cannot land on it. Took two jars, put meat in them, covered one and not the other. The uncovered one had maggots in it.
Leeuwenhoek
Invents the first simple microscope.
“Father of microscopy”.
John needham
Wanted to prove spontaneous generation
Boiled meat broth and covered one of two jars. Both jars had microorganisms after.
Lazzaro spallanzani
Repeated needhams experiment
Boiled broth longer and no organisms were present in sealed flask however they appeared after he broke the seal.
Believed microorganisms were carried in air and multiplies when they had a food suppl
Pasteur
Finally ended the debate for spontaneous generation
Used s shaped flask and boiled solution and let the condensed steam stay in neck. When he tipped it over, microorganisms appeared which disproved spontaneous generation.
Who were the scientists involved in creating the cell theory?
- Francesco redi
- Leeuwenhoek
- John needham
- Lazzaro spallanzani
- Pasteur
Robert hooke
First description of a cell
Saw room like compartments/ hollow sacks that he called cells
Schleiden
Suggested all plants are made of cells
Schwann
Suggested all animal tissue was made of cells
Robert brown
Discovered the centre of the cell which he called the nucleus
Virchow
Observed dividing cells and concluded that all cells can only arise from other cells
Charles spencer
Improved optics in compound microscopes
Knott and ruska
Invented the electron microscope
What are the three types of microscopes
- light microscope
- Scanning electron microscope
- Transmission electron microscope
What are the two types of light microscopes?
- Simple light microscope
- made up of only 1 lense
- Compound light microscope
- made up of two or more lenses
What are the characteristics of a light microscope?
- illuminated by visible light
- magnifies up to 2000 times
- resolution is about 200nm
- to prepare the specimen, it must be killed, stained and fixed.
What are the characteristics of a scanning electron microscope?
- electrons are the source of illumination
- magnification is about 1000-100,000 times
- resolution is about 5nm
- to prepare specimen, it must be fixed, cleaned, and coated with metal
What are the characteristics of a transmission electron microscope?
- source of illumination is electrons
- magnification is about 10,000 to 500,000 times
- resolution is about 0.2nm
- to prepare the specimen, you must fix it, kill it, and dry it
What are the 2 major classifications of cells?
- Prokaryotes
2. Eukaryotes
What are prokaryote cells?
Developed first and for billions of years were the only type of cell in existence.
Are unicellular organisms and are found in all environments.
Largest group of organisms (bc bacteria make up the bulk of the classification)
What are the characteristics of prokaryotes?
- no membran bound organelles
- no membrane bound nucleus
- most have flagella (used for movement)
- have a simple internal structure
- most primitive cell type (appeared four billion years ago)
What are eukaryotic cells?
Cells that are more advanced than prokaryotes. Can be unicellular organisms or multicellular organisms
What are the characteristics of eukaryotic cells?
- have membrane bound organelles
- have a membrane bound nucleus
- complex structure
- appeared approximately 1 billion years ago
What is an organelle?
Are specialized structures within a eukaryotic cell that carry out a specific function.
Why did cells develop organelles?
- Organelles preform specialized functions
- Membrane bound organelles act as containers separating parts of the cell from other parts of the cell
- The membranes of organelles can act as sites for chemical reactions
Fluod mosaic model
A model that describes the cell membrane as being a double layer (bilayer) composed of a phospholipid backbone with proteins embedded throughout. The layer is flexible and able to move.
What does the nucleus function to do?
- transport ribosomes through the nuclear pores
- produce messages or messenger RNA that code for proteins
- store genes on chromosomes
- the nucleolus produces ribosomes
- organize DNA to allow for cell division (make chromosomes)
- organize the uncoiling of DNA to replicate key genes)
The nuclear envelope
Double membrane that surrounds the nucleus
Contains protein channels called nuclear pores
Simple light microscope
Composed on only 1 lense
Compound light microscope
Composed of 2 or more lenses
3 types of objective lenses
- Low power: 4x magnification
- Medium power: 10x magnification
- Hight power: 40x magnification
Cell membrane
A semi permeable membrane that is made up of a phospholipid bi layer with a glycerol head and a fatty acid tail.
What is a cell wall made of?
Cellulose
What support system is used in plant cells
Turgor pressure
Plastid
Organelle that contains photosynthetic pigments
What substances pass through the cell membrane easily?
Water, glucose, oxygen, and alcohol
Plasmosys
Occurs when the cell loses too much water causing it to shrink and die
Factors affecting diffusion
- Temp: high temps increase rate of diffusion
2 size of molecules: the smaller the faster - Size of concentration gradient: the greater the difference in concentration, the faster diffusion occurs
Whats the two types of diffusion?
Simple and facilitated
Both don’t use energy and go in the direction of the concentration gradient however facilitated is for particles that are too large so they use special proteins
Carrier protiens
Proteins used for noncharged molecules
Channel proteins
Proteins used for charged molecules
Tonicity
The relative concentration of solutes on either side of a membrane
Turgor pressure
The swelling of a plant cell because of an increase in water
Crenation
The shrinking of an animal cell because of a loss of water
Cytolysis
The swelling and bursting of an animal cell because of an increase in water
Bulk transport
The movement of large particles through the cell membrane by normal means. This requires energy!! To do this, the membrane folds in on itself to make vesicles
Exocytosis
Movement of large particles out of a cell
Endocytosis
The movement of large particles into a cell
What are the two types of endocytosis?
Phagocytosis - cell eating
Pinocytosis - cell drinking
Extracellular fluid
Fluid located immediately outside a cell that surrounds and bathes a cell
Receptor assisted endocytosis
Special type of endocytosis where transport of materials occurs with the help of special proteins that act as receptors
What cellular process creates ATP?
Cellular respiration
Where does cellular respiration occur?
In the mitochondrion of the cell
What are the two types of respiration?
Aerobic respiration- occurs in the presence of oxygen. releases water, oxygen and 36 ATP molecules
Anaerobic respiration- occurs without oxygen
What are the two types of anaerobic respiration?
Fermentation- breakdown of vegetables and fruits by bacteria. Releases alcohol, carbon dioxide, and 2 ATP Molecules
Lactic acid fermentation- occurs in muscle cells and results in a build up of lactic acid. Releases lactic acid, CO2, and 2 ATP molecules
What is the difference between anaerobic respiration and aerobic respiration?
Anaerobic respiration releases CO2 while aerobic respiration releases O2
What is the connection between respiration and photosynthesis?
They are opposite processes but are complementary as well
What are the two ways a cell can make energy?
- Respiration
2. Photosynthesis
