CELL BIOLOGY Flashcards
what are Cell requirements for life
Energy source
Light or chemical
Matter
Gases such as CO2 and O2
Simple nutrients
Monosaccharides, disaccharides, polysaccharides
Amino acids, fatty acids, glycerol, nucleic acids, ions and H2O
Removal of wastes
CO2, O2, urea, ammonia, uric acid, H2O, ions, metabolic heat
what is Field of View
The maximum area visible when looking through themicroscopeeyepiece (eyepieceFOV), usually quoted as a diameter measurement.
what is Magnification
Magnification refers to the number of times larger an object appears compared to its actual size.
what is Resolution
Resolution is the ability to distinguish between close together but separate object
learn how to calculate magnetism- look in notebook
If you increase the magnification, how will it affect the field of view?
Increase field of view decrease magnification
Decrease field of view increase magnification
learn all the calculations and everything from the powerpoint
learn parts of a microscope from powerpoint
Prokaryotic cells explain
Unicellular organisms Simple cell structure Small: 0.1–5.0 µm in diameter Have a cell membrane and outer cell wall Bacteria also have a capsule outside the cell wall Many have a flagella for movement
Prokaryotic cells (cont.)
Contains some organelles
But unlike eukaryotes, these organelles are not bound by a membrane
E.g. no proper nucleus, but still has DNA
Genetic material is mostly in a single circular DNA chromosome called a genophore.
There are also other smaller rings of DNA rings called plasmids.
Eukaryotic cells
Can be multicellular or unicellular
More complex cell structure
Large: 10-100 µm in diameter
Have a cell membrane and sometimes a cell wall
Eukaryotic cells
Cell compartmentalisation
Organelles bound by internal membranes
E.g. nucleus, mitochondria, chroloplast
Cell compartmentalisation
Multiple membranes mean that organelles can have a different internal composition from the surrounding cytosol and other organelles.
Allows processes that require different environments to occur at the same time, in the same cell
Allows relevant enzymes and reactants to be close together in high concentration and under the right conditions high efficiency
what is cell membrane, nucleus, cytoplasm
one of the membranes of the cytoplasm which keeps it all together
-helps control what goes in and out of the cell
nucleus
-contains chromosomes where inherited info is stored
cytoplasm
-lots of membranes made from proteins and fats
Purpose of the cell membrane
Provides a boundary between the extracellular and intercellular environment
Controls movement between the extracellular space (fluid) and the intracellular space (cytosol)
Phospholipid
Hydro: water
Philic: loving
Phobic: fearing
Phosphate end is polar and therefore hydrophilic (water-loving)
Fatty-acid side is non-polar and therefore hydrophobic (water-hating) – but is ok with non-polar liquids, e.g. oil.
Cholesterol
Stabilises the membrane
At high temps, stops membrane from being too fluid by restricting phospholipid movement
At low temps, stops membrane from being too solid by restricting tight packing of phospholipids
Glycoproteins
A type of molecule made up of a carbohydrate (sugar) linked to a protein that protrudes on the outer surface of the membrane.
Play important roles in cell adhesion and recognition.
Protein channels
Proteins are embedded all throughout the cell membrane and play a wide variety of roles.
One of the most important uses are as transport channels.
Permeability
Cell membranes are said to be semi-permeable ◦ They allow solvent molecules to pass through, but prevent some of the solute molecules from doing so. ◦ Also known as selectively permeable.
What can pass through a
phospholipid bilayer?
Only molecules that are “accepted” in the inner hydrophobic (oily) region! - Small, uncharged molecules - Lipid-soluble molecule
Diffusion
The movement of particles from an area of higher
to lower concentration
There is a concentration gradient
from one side to the other
How to increase rate of diffusion
Increase concentration gradient
◦Increase temperature
◦ The higher the temperature, the faster particles move
◦Reduce size of particles
◦ Allowing faster travel through membranes
And vice versa, to slow down rate of diffusion
Facilitated diffusion
Diffusion of molecules through a membrane via a proteins. No energy is used - Membrane has control over what crosses - Protein can either just provide a path (channel) or bind to the molecule then unbind when its on the inside (carrier). - This is the main way water passes the membrane.
Active transport
When substances are transported across the membrane using energy, often against a concentration gradient. ◦ From low to high conc ◦ Always uses carrier proteins ◦ Crucial in allowing a cell to maintain an internal environment that differs from its external environment
Bulk transport
Uses energy to allow movement of large, polar molecules across the membrane ◦Exocytosis ◦Endocytosis ◦ Pinocytosis (drinking) ◦ Entry of extracellular fluid and substances ◦ Phagocytosis (eating) ◦ Entry of large particles like cell debris or bacteria
Aquaporins
Protein channels that facilitate the diffusion of water through membranes
Particles diffuse across the semi-permeable membrane, down the concentration gradient, until equilibrium is reached
What if the solute particle cannot pass through the membrane?
Can equilibrium still be reached?
If water can still pass through the membrane, then it will move to achieve equilibrium!
Osmosis
Osmosis is the net diffusion of water molecules across a semi-permeable membrane
Just like regular diffusion, but of water!
The concentration gradient is called an osmotic gradient
The pressure that causes the water to move along this gradient is called osmotic pressure.
Water moves from hypotonic into hypertonic
Hypotonic:
The solution with the lower conc of solute
(and high conc of water)
Hypertonic:
The solution with the high conc of solute
(and lower conc of water)
Isotonic:
Both solutions have the same conc of solutes
what is metabolism
the chemical reactions in the body’s cells that change food into energy
what are the elements of cardiovascular system
Blood- the medium of transport
Heart- the pump
Vessels- the pathway
Explain Blood
it is a complex mixture containing:
1. cells- RBS WBC Platelets
2. Plasma
RBCs are flattened discs which carry oxygen around the body.
Oxygen (O2) is held loosely by a protein called haemoglobin.
Haemoglobin has an iron molecule at its core, which gives it a red colour.
WBCs are much fewer in number.
They help protect the body against disease
Platelets are tiny cells which enable the blood to clot.
Plasma is a yellow liquid in which the cells float.
Explain heart
The energy to move blood through the body is provided by the heart.
70 mL per beat
280 L per day
The heart begins beating in the embryo 3 wks after fertilisation
- from a tiny cluster of cardiac cells
explain vessels
The pathway which carries the blood is a system of tubes called blood vessels There are three major kinds of vessels: 1. Arteries 2. Veins 3. Capillaries
what are arteries
Arteries always carry blood AWAY from the heart. Arteries: have a red-coloured lining have thick, muscular walls usually carry blood under high pressure
what are veins
Veins always carry blood TO the heart. Veins: have a bluish lining have thin walls usually carry blood under low pressure
what are arteries
Arteries branch into smaller and smaller arterioles. Eventually they become capillaries, tiny vessels which reach into every tissue.
Capillaries branch into larger and larger venules, which then join to become veins.
explain lymphatic system
The lymphatic system performs two roles: 1. Circulation 2. Disease resistance (immune response) Since the heart is constantly pumping, fluid is always being pushed into body tissues. Without the lymphatic system, those tissues would swell up. The lymphatic system has: 1. Lymph basically plasma (no cells) 2. Lymph vessels thin walled with valves 3. Lymph ducts larger vessels which empty lymph into veins 4. Lymph nodes bean-shaped lumps for lymph collection the location of WBC development
how does fluid move throughout lymphatic system
Plasma leaves the blood stream, entering between tissue cells.
This intercellular fluid moves through the tissue, collecting wastes as it goes.
The fluid passes into lymph capillaries and is now called lymph.
Lymph moves along the vessels until it reaches a lymph node where WBCs destroy pathogens.
Lymph then moves through to a lymph duct, which returns the fluid to a large vein, completing the circuit.
Respiratory system
In the human body there are two kinds of respiration:
1. Cellular respiration 2. Pulmonary respiration
Cellular respiration is a chemical process during which energy molecules are broken down.
Pulmonary respiration is the process by which gases are breathed in and out.
2 major sections of respiratory system
The respiratory system has two major sections:
1. Upper respiratory system 2. Lower respiratory system
main parts of resp system
The nose and mouth are air entry points.
The pharynx connects the mouth with the trachea.
The epiglottis is a flap of tissue which prevents food going down the airway
The trachea is a rigid tube lined with cartilage
The lungs are spongy tissue made of tubes and sacs.
Alveoli (singular alveolus) are tiny sacs grouped in clusters at the end of the bronchioles.
They have very thin membranes and a high sa:vol.
They are supplied by a dense network of capillaries.
It is here that gas exchange occurs between air and the blood stream.
The diaphragm is a sheet of muscle separating the chest from the abdomen.
The inter-costal muscles join the ribs to each other
Respiratory Process
Inter-costal muscles pull the ribs apart
The diaphragm contracts
These two actions expand the chest cavity, creating a lower pressure.
The lung tissues expand to fill the chest cavity
Air rushes in through the mouth & trachea (etc.)
During its passage down the airways, air is filtered by cilia, warmed and humidified
Once it reaches the alveoli, oxygen passes through the membrane into the blood in the capillaries
- At the same time, CO2 diffuses from the blood out into the alveoli
- The inter-costal & diaphragm muscles relax
- The chest cavity shrinks
- Air is expelled
Respiratory Disease
Respiratory disease can be caused by:
1. Pathogens (e.g., bacteria) 2. Lifestyle impacts (e.g., smoking)
Photosynthesis
Solar energy is converted to chemical bond energy in the process of photosynthesis. This bond energy is then released for cellular use via the process of respiration. Photosynthesis occurs in chloroplasts. occurs in two phases: Phase 1: Light reactions - require sunlight energy
what are autotrophs and heterotrophs
Organisms which construct their own energy storage molecules (‘food’) are called autotrophs.
Organisms which gather their energy from other organisms are called heterotrophs
what are The two major energy storage molecules
The two major energy storage molecules in biological systems are glucose and ATP Glucose - quite small - quite stable - universal in the biosphere - not useable at the organelle level ATP: - adenosine tri-phosphate - ADP + P = ATP - the creation of the bond stores energy - breaking the bond liberates energy - ATP directly fuels organelle activity
what is the photosynthesis equation
CO2 + H20 —— C6H12O6 + O2
what are light and dark reaction
Light:
AKA “Light Dependent Reactions” as they require solar energy
Occur in the thylakoids of grana
Does not result in the production of sugar
Dark-
AKA ‘Light Independent Reactions’ as they occur constantly
Depend on the outputs of the light reactions
Occur in the stroma of the chloroplasts
Results in the formation of sugars
(CH2O)n
Process Calvin Cycle
what is visible light spectrum
The complete set of rainbow colours is known as the visible light spectrum.
The visible spectrum is itself only a small fraction of the complete electro-magnetic (EM) spectrum.
All EM energy, including light, moves in waves. The distance from the peak of one wave to the peak of the next is known as its wavelength
why are plants green
Red light is absorbed most by chlorophyll, followed by blue light. they energise electrons and increase rate of photosynthesis
Green and yellow light are mostly reflected. This is the reason plants look green
