Cells as a basis of life Flashcards
What is a cell?
The building blocks of life. They make up everything. All cells are similar but differ in some way.
What are the 6 kingdoms?
Archaea
Eubacteria
Protista
Fungi
Plantae
Animalia
What are the three domains?
Archaea
Bacteria
Eukarya (Eukaryotes)
What are the types of Bacteria?
Cyanobacteria- Nostoc
Stromatolites- Green Algae
Nitrogen fixing bacteria- Bacillus
What are characteristics of Eukaryotic cells?
- Have membrane-bound organelles
- DNA contained within a nucleus
- Range from 10-100um
What is the ‘Cell Theory’?
- Cells are the smallest units of life
- All living things are made up of cells
- All cells come from preexisting cells
What are prokaryotes?
Organisms that are made up of a single cell (unicellular)
What are the types of Archaea?
Methanogens- Methanosarcina Barkeri
Halophiles- Halobacterium
Thermophiles- Alicyclobacillus
WHat are some characteristics of Prokaryotes?
- Surrounded by cell wall
- Does not have membrane bound organelles
- No nucleus so DNA moves freely within Cytoplasm
- Ranges in size from 0.1 - 10um
What are the two types of prokaryotes and where are they found?
Archaea and Bacteria
Found in most environments and inside our bodies
Can be extremophiles (lives in harsh environemnts)
What can Eukaryotes be classified into?
Plant, Animal, Fungi, Protist
What are examples of plant eukaryotes
Algae
Moss
Ferns
Conifers
Flowering Plants
What are examples of animal eukaryotes?
Invertabrates- worms, insects
Vertebrates- fish, amphibians, reptiles, birds, mammals
What are examples of fungi eukaryotes?
Mushrooms
Yeast
What are examples of Protist eukaryotes?
Amoeba
Paramecium
Euglena
What is the equation for scale?
Scale= Actual length of cell/ the length of the drawing
What is a microscope?
A tool that uses lenses to enlarge or magnify objects to make them easier to observe
What is a compound microscope?
A microscope that uses two sets of lenses to enlarge the image
What specimens can you see with a light microscope?
Thin sections or whole organism (dead or alive)
What is the treatment for a light microscope?
Stains can be applied to highligth different components of the cell
What image can you see with a light microscope and at what magnification?
Can view inside a cell or the whole cell at up to 1500x magnification dependieng on lense
What are the advantages of a ligth microscope?
- Live Specimens can be viewed
- Easy to prepare specimens slides
- Stains can easily be applied to highlight aspects of the cell
What are the disadvantages of a light microscope?
Lower magnification and resolution so less detail can be seen.
What are the types of electron microscopes?
Transmission Electron Microscope
Scanning Electron Microscope
What specimen can be viewed with an Transmission ELectron Microscope?
Ultra thin section or whole microscopic dead organism
What is the treatment on an Transmission ELectron Microscope?
Stained, dehydrated or fixed specimens embedded in resin and sectioned.
What image can you see with an Transmission ELectron Microscope?
Can view inside a cell or the whole organism, with multiple images to create 3D view. The electrons are transmitted through the specimen.
What is the treatment for a Scanning Electron Microscope?
Stained, dehydrated, fixed specimens, coated in thin layer of metal atoms.
What specimens can be viewed with a Scanning Electron Microscope?
Thin Section or whole organism (dead or alive)
How is the imaged processed and what image do we see from a Scanning Electron Microscope?
Electrons bombard specimen and rebound pattern. We get see a 3D surface view.
What are the advantages of electon microscopes?
- Specimens can be viwed with greater detail due to higher magnification and resolution
What is the FOV diameter for x1000 magnification?
150um
What are the disadvantages of using an electron microscope?
- Preparation of specimens is time consuming, difficult and expensive
- Cannot view live specimens with Transmission Microscope
- Harsh treatment of specimens can distort the true nature of the structure os cells being viewed.
Why are microscopes important?
- it allowed scientists to view microscopic organisms
- Cells can be examined inmore detail and organelles identified
- Enabled scientists to identify the nucleus and DNA
- Genes that caused diseases could be identified
How do you calculate magnification?
Multiply the power of ocular lens by power of objective lens
E.g. x10 x x4 = x40 magnification.
What is the formula for estimating cell size?
Cell Size= Diameter of field of view / No. of cells across field of view
What is the FOV diameter for x100 magnification?
1.5mm
What is the FOV diameter for x40 magnification?
4.5mm
How do you convert from mm to um?
mm x 1000
4mm= 4000um
What is the FOV diameter for x400 magnification?
450um
What are the two microscopy techniques and thier purpose?
Wet mounts- improves a sample’s appearance and enhances visible detail.
Stains- highlights specific features, mostly used on dead specimens.
What is a model?
Physical, conceptual or mathematical representation of a real phenomenon that is difficult to observe directly.
What are the advantages of using scientific models?
- provides information when the object or process can’t be observed directly.
- use to notice patterns and revise representations
- Can break down a concept into similar terms with a visual component.
- Helps visualise ideas or abstract concepts
- Models save time, money and lives.
- Can be used to make and test predictions
- Can be changed as theories change or update.
What are the disadvantages of a scientific model?
- Usually simplified versions have missing information and details
- Accuracy can be lost
- Models do not behave exactly like the thing they represent.
What substances are transported into a cell?
- Food
- Sugars
- Proteins
- Fats
- Salts
- O2
- H2O
What is transported out of the cell?
- Wastes
- Ammonia
- Salts
- CO2
- H2O
- Products
- Proteins
Define Concentration gradient?
The difference in concenetration between sections of fluid, either within a fluid body or between a semipermeable membrane.
What are the two types of transport?
Passive Transport
- Diffusion
- Osmosis
Active Transport
- Endocytosis
- Exocytosis
What is the difference between Active and Pasive transport?
Passive Transport does not require energy and follows the concentration gradient (high to low concentration) whereas Active transport requires energy and goes against the concentration gradient (low to high concentration)
What is an isotonic solution?
When both inside and outside the membrane have an equal concentration.
Define Diffusion
The movement of any molecule from an area of high concentration to low concentration until equilibrium is achieved.
What is the difference between simple and facilitated diffusion?
In simple diffusion small hydrophobic uncharged polar molecules move through the membrane where as is facilitated diffusion the molecule is transported through the membrane by a carrier protein. The molecules are usually large and charged.
What is osmosis?
The diffusion of water molecules across a membrane. It moves from a dilute solution (more water) to a concentrated solution (less water) until equillibrium is achieved.
What is a hypertonic solution?
When outside the membrane has a higher concentration than inside.
What is a hypotonic solution?
When outside the membrane has a lower concentration than inside.
What is endocytosis?
What material is brought into the cell. The cell membrane creates a vesicle around it and brings it into the cytoplasm.
What is exocytosis?
When wastes are removed from the cell. A secretory vesicle is created around the waste in the cytoplasm and is removed through membrane.
What factors can impact transport?
- Size of molecule- small particle diffuse easier
- Temperature- higher temp. = faster diffusion
- Concentration gradient
- Surface Area to volume ratio- higher SA:V ratio= more efficient diffusion
What are characteristics of organic molecules?
- Always contain Carbon atoms
- Formed by living things
- E.g. Carbohydrates, Lipids(fats), Protiens or Nucleic Acids
What are characteristics of Inorganic molecules?
- Usually does not contain carbon atoms (if present it is not attached to hydrogen e.g. CO2)
- Not formed by living things
- E.g. Water, Oxygen, Salts, CO2
What is the purpose of Water in cells?
-It makes up 70-90% of most organisms
-It is am important solovent and transport medium
- Chemical reaction take place in and include water.
What is the importance of Carbohydrates (CH2O) in organisms?
-It is an important energy sources and structural component of organisms
-It is needed for repiration
-It is stored as fat and used as needed
What are some common forms of CH2O?
Sucrose (table sugar)
lactose (milk sugar)
Fructose (fruit sugar)
Starch (food stored in plants)
Cellulose (Cell wall in plants)
What is the difference between Autotrophs and heterotrophs?
Autotrophs make their own food for energy while Heterotrophs eat other organisms to gain energy.
What does ATP and ADP stand for? What is their relationship?
ATP- Adenosine Triphosphate
ADP- Adenosine Diphosphate
Energy in cells is released when ATP breaks down to ADP and then is converted back.
Where does ATP come from in plants?
Plants produce glucose during photosynthesis which is the used in cellular respiration to produce energy in the form of ATP.
How is ATP produced in animals?
Plants eat other organisms to get glucose which is then used in respiration to form ATP.
Equation for photosynthesis?
6CO2 +6H2O > C6H12O6 +6O2
What are the two stages of Photosynthesis?
Light dependent
Light independent
What happens in the light dependent stage?
Energy from the sun is absorbed by chlorophyll pigments and is converted to chemical energy. This is then used to split water into hydrogen and oxygen.
What happens in the light independent stage?
Hydrogen is released from the first reaction and combines with Carbon to form sugars. This stage requires energy and occurs in the stroma of the chloroplasts.
Equation for respiration.
C6H12O6+6O2 > 6CO2+6H2O+ATP
What happens in step 1 of respiration?
Glucose molecules are split into two 3 carbon molecules and 2 ATP molecules are produced. this process occurs in the cytoplasm.
What happens in step 2 of respiration?
Carbon molecules move to mitochondria to be broken up by oxygen into carbon dioxide and water. This process results in 36 molecules of ATP
What is anaerobic respiration?
When organisms don’t have enough oxygen molecules so they use electron acceptors like Lactic Acid or the process of Alcohol fermentation instead.
Purpose of mitochondria.
-Powerhouse of the cell
-Produces ATP necessary for survival
Structure of mitochondria
Double membrane system consisting of inner and outer mitochondrial membranes
Function of Cytoplasm
Move, maintain cell shape and structure, protect, store macromolecules and lead chemical processes.
Structure of cytoplasm
Jelly-like fluid inside of cells.
Function of vacuole
Stores water, waste, nutrients and other fluid
Structure of Vacuole
Blob like organelle
Smaller in animals than plants
Function of Rough ER
Transports, modifies and packages proteins
Structure of Rough ER
Has ribosomes and a large lace-like sac
Function of Smooth ER
Creates lipids and phospholipids
Structure of Smooth ER
Tube likes with no ribosomes.
Function of Ribosomes
Synthesise proteins
Structure of Ribosomes
Intercellular structure made of RNA and protein
Function of Cholorplasts
To produce energy through photosynthesis
Structure of Chloroplasts
Green with double bound membrane and little disks
Function of Nucleus
Store genetic information
Control centre of cell
Structure of Nucleus
In middle of cell, surrounded by filament, has a double membrane envelope
Function of Nucleoid
Makes and assembles ribosomes
Structure of Nucleoid
Composed of RNA, DNA and protein.
Function of Golgi Apparatus
Helps process and package protein and lipid molecules
Structure of Golgi Apparatus
Series of stacked membranes
Function of Lysosomes
Digestive system of cell, Enzymes waste disposal
Structure of Lysosomes
Circular shaped sac filled with hydrolytic enzymes
Function of Cell Wall
Provides protection and support to cells
Structure of Cell wall
-Cell wall found next to membrane
-In plants made of cellulose.
Purpose of Phosphoplipid
Gives the cell membrane flexibility and makes up the cell wall
Purpose of Phosphoplipid Head
Faces outwards, is attracted to water. Builds membrane structure
Purpose of Fatty acid lipid Tail
Reppels water, Separates intercellular and extracellular environments
Purpose of Glycolipid
Plays a role in allowing body to recognise self and non- self
Purpose of Glycoprotein
Plays a role in cell signalling (messaging)
Purpose of Carbohydrates
Cell adhesion and recognition involved in immune system
Purpose of Cholestrol in bilayer
Prevents phospholipids from crowding and connects them together
Purpose of Integral Protein
Provides stability
Purpose of Protein Channel
Allows larger molecules to travel in and out of the cell
Purpose of Phospholipid bilayer
Keeps things in and out
