Lecture 1 Flashcards
What is life?
Is an emergent property of a particular arrangement of certain molecules.
response to the env
Exchange of material with env
Metabolism
Growth
Reproduction
What is the cell?
Cell is the fundamental unit of living things
Two types of cells
Prokaryotic cell: no true nucleus (ex: bacteria)
Eukaryotic cell: have a true nucleus (ex: algae, we are…)
Unicellular
Each cell carries out all life processes
Multicellular
Made up of many cells with different cells specialized to perform different functions.
What are prokaryotic cells?
Prokaryotic cells can’t be multicellular are mostly monocellular.
Size comparison between plant cell, animal cell and bacterium
Plant cell > animal cell > bacterium
Whats the size of most eukaryotic cells
Most eukaryotic cells are around 10^-4m and 10^-5m (100-10 micrometer).
When does surface to volume ratio increases?
Surface to volume ratio increases the smaller something gets.
Why are cells small?
Cells are small because they require a high surface to volume ratio to exchange materials with their environment.
What is the cell full of? (prokaryotic cell, bacterial)
Cell is full of a semi-fluid aka cytosol.
What is cytosol?
a complex mixture of enzyme and many other molecules in water. Many chemical reactions take place here.
Cytosol pic
What is the plasma membrane/cell membrane?
A boundary between cell and environment. Two parts are non-polar tails (two fatty acids) and one part is a polar head, also called a phospholipid. The polar head will stick to the water molecules with hydrogen bonds. The non-polar tails turn around and face each other, it creates a phospholipid bilayer.
What does the Phospholipid bilayer do?
It controls what comes and goes out of the cell.
What is the Phospholipid bilayer?
a two-layered arrangement of phosphate and lipid molecules that form a cell membrane
Phospholipid bilayer image here
Phospholipid bilayer
What does the non-polar layer do?
The non-polar layer makes it relatively impermeable to polar molecules. When a polar molecule comes close, it gets pulled back (attention: not pushed by the membrane), have trouble crossing it.
How do non-polar molecules diffuse?
However, non-polar molecules (ex: O2, CO2, lipids) diffuse through freely.
How do small polar molecules diffuse?
Small polar molecules (ex: H2O, ethanol) diffuse through much more slowly
How do larger polar molecules and ions diffuse?
larger polar molecules (ex: glucose) and ions diffuse through hardly at all.
What are embedded in the plasma membrane?
There are proteins embedded in the plasma membrane.
The plasma membrane is…
a semi-permeable membrane
What and how is constantly moving along the membrane?
Proteins and phospholipids are constantly moving along the membrane as it is fluid.
What are the four types of proteins along the membrane?
Channel protein, gated channel proteins, Carrier proteins, Active transport protein.
What is the channel protein?
AllowS certain molecules to pass through. Don’t have any control on direction of movement. Only very specific molecules are allowed to pass through (depends on size and chemical properties of amino acids making up the channel).
What are aquaporins?
Are channel proteins that allow water to pass through.
What are gated channel proteins?
Same but the only diff is that it can open and close (they have a gate).
What are carrier proteins?
pick up a specific molecule, flip around and release it on the other side, no control on direction of movement (but goes both ways). Is used for bigger molecules.
Which proteins facilitate diffusion and apply passive transport?
Channel protein, Gated channel proteins and Carrier proteins facilitate diffusion, don’t put things into or out of the cell, called passive transport.
What are active transport proteins?
functions like a carrier protein BUT it uses energy from the cell
in the form of ATP in order to function and they move materials in
a specific direction
Ribosomes
are the site of protein synthesis (aka making)
Nucleoid
Where there is most of the genetic information in a prokaryotic cell. Made of a single loop double-stranded DNA.
Cell wall
Is rigid, gives cell shape and protects it from bursting.
Flagellum
Rotates to provide mobility
Thylakoid
Provides a membrane for photosynthesis
Capsule
Sticky, protects cell from attack or dehydration
Plasmid
Accessory genetic information
nucleus and prokaryotic cell
Prokaryotic cells: no true nucleus
Nucleus and Eukaryotic cell
Eukaryotic cells: have a true nucleus
Unicellular
Each cell carries out all life processes
Bacterial Cells
no true nucleus
no endoplasmic reticulum
no Golgi apparatus
no mitochondria
no chloroplasts
no vesicles or vacuoles
no centrosome
Animal Cells
no cell wall
no plasmodesmata
no chloroplasts
no central vacuole
Plant Cells
no centrosome
no lysosomes
cell wall: cellulose
Fungal Cells
eukaryotic
cell wall: chitin
pores between cells
no plasmodesmata
no centrosome
no chloroplasts
