Week 2 Chapter 4, 5, 6, 7 Flashcards
What are the ways cells interact with the environment
Cells absorb nutrients through their surfaces
Cells get rid of wastes through their surfaces
A small cell has a lot of surface area per volume
A large cell has much less surface area per volume:
PROKARYOTIC CELLS
Small cell size: (tend to be; not all) Less than 10 m(1 1millionth of a meter) No nucleus No internal organelles: Ribosomes are small: 70s Simple; structurally not complicated
organelles
- : a structure inside a cell that is bound or surrounded by its own membrane
Ribosome
– accumulations of proteins and nucleic acid
- Responsible in all cells of protein production
Why are cells smalll
There is a limit in the size of cells because of the way cells interact with the environment.
- More space more surface area easier for interaction
- Amount of surface area not going to be able to handle demand of big volume
- Matter of effeciency
Cytoplasm
– all liquid part
- Everything inside the cell is suspended in liquid cytoplasm
Eukaryotic Cells
Bigger; have nucleus
Large size ribosomes : 80s
Large size:10m – 1000m (1 mm)
(human egg is a single cell; can see naked eye)
Nucleus : surrounded by a double membrane
Eukaryotic Cells
- Animals
Nucleus: surrounded by a double membrane
- Have holes
- Material inside cell: chromatin
- Chormatin: genetic material: DNA and protein
- Nucleolus: (another structure inside nucleu)
Nucleolus
o Condensed chromatin
o Site of RNA synthesis
o DNA in long strand in pieces; linear pieces - chromosome
In RNA once piece circular
o Prokaryotic – one chromosome
o Eurkaryotic – many chormosomes
Number – indicative of characteristcis of particular organism
Human have different than other animals
The internal Organelles of Eukaryotic Cells
- Membrane-bound nucleus
- Endoplasmic reticulum
- Golgi apparatus
- Mitochondria
- Chloroplasts
- Vacuoles
- Lysosomes
- Cytoskeleton
- Flagella and Cilia
Endoplasmic reticulum
Long labrynth like membrane that fills up good portion of cytoplasm
- Two kinds
- Rougn ER:
- Smooth ER:
Rougn ER:
- studded with ribosomes
- site of protein synthesis
Smooth ER:
- no ribosomes
- site of lipid synthesis
o Connected to rough er
Golgi apparatus
- Protein processing and packaging
- (secretory proteins)
- Responsible for taking protein made in ER and packagaging them
- Any protein that cell is going to get rid of or secrete has to be package and its done in golgi apparatus
Mitochondria
- Cell powerhouse; site ofATP synthesis
- Production of energy inside a cell
- All energy takes form of ATP
Chloroplasts
- absorbs sunlight to do photosynthesis
- Leafy plants and algae only
- Photosynthesis (ATP from sunlight) and CO2 incorporation
Vacuoles
- Storage ‘compartments’: starch, enzymes
- Big;
vesicles
small storage compartments
Lysosomes
contain digestive enzymes to degrade engulfed material
Cytoskeleton
- Microtubules (tubulin)
- microfilaments (actin)
- centrioles
Microtubules (tubulin):
- organize and move the organelles
- responsible for cell shape
o Not bound by membrane
o protein
- microfilaments (actin):
movement of the cell (pseudopodia) and organelles (cyclosis)
o movement of organelles within cells
- centrioles
: organization of cell division
- organize formation of microtubules
o present during cell division
o difficult to find when cell is divided
Flagella and cilia
- ‘organs’ of locomotion:
flagella:
long, relatively few per cell
- Outside of cells
- Cells with flagella – whip back and forth – push through environment
Cilia:
- short, many thousands per cell outside
- Celia all move together – oars of ships – all pushing cell through environment
o Allow cell to spin; travel straight lines, reverse, turn around, etc
Cell membrane
o Phospholipid bilayer, imbedded with proteins
Polar charged with + and –
Tail: hydrophobic
Head: hydrophilic
Outside of cell is mostly water
Inside of cells cytoplasm is mostly water
All cell membrane are made up of phospholipid
Proteins of Cell Membranes
Some hangs around outside : peripheral protein
Span membrane; imbedded: integral protein
In order to exist in environment: they have to be matched; in part must be hydrophilic
Middle in membrane: hydrophobic
cholesterol in cell membrane
A necessary part of living things
Embedded in bilayer to stabilize more rigid the membrane
Cell wall
o Most animal cells lack a cell wall; plant have cell walls made of cellulose(polysaccharide)
o Bacterial cells have cell walls made of a polysaccharide: peptidoglycan
Cell walls: made up of carbohydrates
o True in almost all cases of cell walls
Diffusion
Diffusion across membrane is selective:
o : movement of molecules from an area of high density (high concentration) to an area of low density
Osmosis
o : movement of water across a membrane in response to solute differences outside and inside the cell
- Not only Diffusion of water through air, across a membrane; from more concentrated water to less concentrated water
- Water: solvent
Solvent
-anything that has something else dissolved in it o Solution of water and salt Water is the solvent Salt is the solute Together they make a solution
Osmosis
cell
o Water inside and outside
o Inside – cytoplasm = water + bunch of different solute (salt, protein, etc)
o Water is going to move across through membrane in response concentration of water – from more to less)
[[H2O] + [salt]
If salt goes up water goes down vice versa
WFS – water follows solute
• Water goes where solute is higher
o Equal – travel equaly inside as outside
Isotonic
Osmosis
when solute is lower
Hypotonic – swell and burst
Osmosis
- when solute is higher
Hypertonic – shrink
How molecules cross the plasma membrane
- Hydrophilic edge
- Hydrophobic inside
- Difuse through water and very very small uncharged particles
Diffusion across membrane is selective
The three transport
- (movement down the gradient or along the gradient or sometimes with the gradient)
passive transport
facilitated transport
active transport
o Gradient
– the difference in concentration
- Passive transport:
o Simple diffusion (osmosis)
o movement of solutes across membrane with a gradient (from higher concentration to lower concentration
facilitated transport :
-movement of solutes across membrane with a gradient (from higher concentration to lower concentration dependent on presence of carrier proteins
o Requires special protein present in membrane that allow those molecules (bigger) to pass through membrane however they’re still going to do it without expendure of energy of cell and with gradient/along with gradient
active transport :
movement of solutes across membrane against a gradient : requires transport protein and uses energy
-o Energy used is ATP to move across
Membrane-assisted transport
endocytosis
exocytosis
endocytosis
- get into the cell
phagocytosis and pinocytosis
Phagocytosis
- The changing the deformation of cell membrane itself to wrap around big object like cell and engulf foreign material – result is a vacuole
- A way that some cells eat
- Old rbc gets recycled – engulfed then get rid of waste
- Big things big molecules
- Whole cells
- Wbc get rid of bacteria, invaders
Pinocytosis
- Difference is size
- Small molecules but lots of them
- Result is a vesicles
- Molecules
o Exocytosis
– out of the cell
• Protein needs to export
• Cell produce material inside vesicle then fuse with membrane then outs
Reverse of endocytosis
Chromatin :
genetic material : DNA and protein
Nucleolus
: condensed chromatin
site of RNA synthesis
Cell wall
- Most animal cells lack a cell wall
- plant have cell walls made of cellulose (polysaccharide)
- Bacterial cells have cell walls made of a polysaccharide : peptidoglycan
Hypertonic solution
- Cell shrink o Shrinking animal cell that doesn’t have a cell wall – ends with a shrank cell Crenation o Plant cell have a cell wall Cell membrane separate with cell wall Plasmolysis
Hypotonic solution
- Burst
o Lysis
Why if in hospital give IV – sugar, saline solution – give isotonic solution to introduce into bloodstream if not rbc will burst
isotonic solution
- has no effect on the passage of water into or out of the cell
ENERGY and ENTROPY
1st and 2nd Law of Thermodynamics :
Energy can neither be created nor destroyed only its form can be changed.
Changing energy from one form to another is never 100% efficient some energy will be lost as unusable heat.
Inefficient energy transfer tends to increase disorder or entropy in the universe.
- Measure of loss is entropy
COUPLED REACTIONS
Exergonic reactions are coupled with endergonic reactions in order for the energy released from the exergonic reactions to be stored or used in powering endergonic reactions.
exergonic
- Reaction that gives up energy
- Give up work – ergonic
Endergonic
o – require work/energy
why does the coupling of Exergonic and endorgonic with each other in biological system important
if not then energy produced cannot be used by cell to do work
ATP
: adenosine triphosphate is the chemical that cells use to transfer energy from one reaction to another
- main compound responsible for coupling
- energy currency of the cell
o Thing make everything else happen
- Anabolic reactions transfer energy from ATP to complex molecules