Chapter 1 + 2 Flashcards
Importance of water
- Most abundant compound in our bodies
- Main solvent for many organic molecules present
- Ideal medium for metabolism
H2O structure
- Single oxygen atom (negative charge) covalently bonded with two hydrogen atoms (positive charge)
Water molecules are highly…
Cohesive
Water molecules are cohesive meaning
Individual molecules of water are highly attracted to another
Causes of water being cohesive
- Hydrogen bonding
- Slight positive/negative charges
Properties of water (8)
- Boils at 100 degrees Celsius
- Less dense as ice
- Transparent
- High specific heat capacity
- Evaporative cooling
- pH of 7 (pure)
- Surface tension
- Naturally exists in 3 states
Reasons for boiling point at 100 degrees
Hydrogen bonds no longer hold together molecules
Reasons for ice being less dense
- Less movement within molecule when frozen
- Lattice shape
Hydrophilic definition
Substances that dissolve readily in water
Other terms for hydrophilic
Polar, lipophobic
Hydrophobic definition
Substances that do not dissolve readily in water, but dissolve readily in lipids
Other terms for hydrophobic
Non-polar, lipophilic
Examples of hydrophobic substances
Alcohol, ether
How substances dissolve
The positive and negative charge of water attracts ions in substance and break substance apart causing it to ionise.
How pH is worked out
Ratio of OH- and H+ ions
Neutral pH
7
Acidic pH
Less than 7
Basic pH
More than 7
How pHis kept constant by body
Cells produce and use hydrogen ions
Hydrogen bonds maximum partners (in water)
4
Main types of organic molecules
Carbohydrates, lipids, proteins, nucleic acids
Monomers definition
Smaller molecules (subunits) that give rise to the polymer
Polymer definition
Molecules that consist of many repeating subunits
How polymers are formed
Condensation reactions,
Anabolic, endergonic
How polymers are broken down
Hydrolysis reaction
Catabolic, exergonic
Carbohydrates elements
Carbon, hydrogen, oxygen
Ratio of elements in carbohydrates
1:2:1
Subunits of carbohydrates
Monosaccharides, disaccharides
Polymer of carbohydrates
Polysaccharides
Monosaccharides
A molecule that is comprised of a single sugar unit
Polysaccharides
A molecule that is comprised of many sugar units
Disaccharides
Molecule that is comprised of two sugar units
Monosaccharide examples (4)
Glucose, fructose, galactose, mannose
Glucose
- hexose sugar
- most common source of energy
- C6H12O6
Two types of glucose
Alpha and beta glucose
Fructose
Pentose sugar, in fruit
Disaccharide examples (3)
Sucrose, maltose, lactose
Sucrose
Glucose + fructose
Processed sugar
Form in plants (phloem)
Lactose
Glucose + galactose
Maltose
Glucose + glucose
Polysaccharide examples (6)
Starch, glycogen, cellulose, chitin, pectin, inulin
Starch properties (branched or not, role, solubility, type of glucose)
Branched
Storage of energy in plants (granules)
Slightly soluble
Alpha glucose
Glycogen properties (branched or not, role, solubility, type of glucose)
Highly branched (more than cellulose)
Energy storage in animals
Slightly soluble in water
Alpha glucose
Cellulose properties (branched or not, role, solubility, type of glucose)
Unbranched
Structural component in cell walls of plants used for structure and strength
Insoluble
Beta glucose
Energy storage in plants (not just starch)
Granules in amyloplasts
Simple carbohydrates
Carbohydrates containing one or two sugar units
Complex carbohydrates
Many sugar units
Inorganic compounds examples
Salts, water, O2, CO2, minerals
Bonding that holds together carbohydrates
glycosidic linkages
Lipid elements
carbon, hydrogen, oxygen
How to tell difference between lipid and carbohydrate
in lipid, there is usually much less oxygen
Do lipids or carbohydrates produce more energy
lipids as they are more dense
Examples of lipids (4.5)
fats and oils, phospholipids, waxes, steroids
Fats and oils are known as
triglycerides/triacylglycerols
Triglycerol comprised of
single glycerol molecule bonded to 3 fatty acid tails
Are lipids polymers
no, as their subunits are discrete and non-repeating
Are lipids soluble in water
no
How are triglycerides stored in the body
adipose tissue
Purpose of adipose tissue
protects vital organs by cushioning, absorbs impact, insulator, source of fats, energy
Cholesterol structure
4 rings
Purpose of cholesterol in phospholipid bilayer
fluidity to prevent solidification, keeps in place, acts as barrier between phospholipids
Use of steroids
signalling molecules, muscle repair
Use of wax
surface coating
Phospholipids definition
A lipid molecule found in the membranes of cells, that are comprised of a glycerol molecule attached to a hydrophilic phosphate head, and a two hydrophobic fatty acids tails.
Phospholipids structure
phosphate group, glycerol molecules, two fatty acid molecules
Are fatty acids of phospholipids saturated or unsaturated
one is saturated, one is unsaturated
Unsaturated meaning
if have one or more double carbon bonds
Saturated meaning
are saturated with hydrogens; have the maximum possible number of hydrogens
Is phospholipid hydrophilic or hydrophobic
head is hydrophilic, tails are hydrophobic
Why do fatty acid tails face in
because they are hydrophobic
Amino acid elements
C, H, O, N, generally S
Subunits of proteins
amino acids
How many naturally occurring amino acids are there
20
Amino acids can be (polarity e.t.c.)
nonpolar, polar, electrically charged, acidic or basic
Structure of amino acid
carboxyl group (-COOH), amino group (-NH2), variable R/Z group
Dipeptide
2 amino acids
Tri-peptide
3 amino acids
Polypeptide
many amino acids
When to call it protein vs polypeptide
it’s a protein if it’s extremely long, multiple separate amino chains, globular
Globular proteins
soluble, lock and key
Examples of globular proteins (5)
enzymes, messenger molecules, membrane channel/carrier proteins, regulatory proteins, defensive
Fibrous proteins
insoluble, structural use
Amino acids are….
directional
Type of bonding amino acids use
peptide bonding
Secondary structure
localised coiling and folding of segments of the polypeptide chain through hydrogen bonding
The two types of secondary structure folding
alpha helices, beta pleated sheet
Tertiary structure
overall 3-D structure and irregular folding of the protein due to global coiling and folding
What controls function of protein/enzyme
tertiary structure
Quaternary structure
multiple polypeptide chains (held together through hydrogen bonding, ionic interactions, covalent bonding and hydrophobic interactions) that form a final protein
Two types of nucleic acids
DNA, RNA
DNA stands for
deoxyribonucleic acid
RNA stands for
ribonucleic acid
Locations of DNA
nucleus, mitochondria, chloroplast
Types of RNA
messenger, transfer, ribosomal
mRNA
transcription
tRNA
carries amino acids for translation
rRNA
structural component of ribosomes, also located in nucleolus
Monomers of nucleic acids
nucleotides
Two types of nucleotides
DNA nucleotides, RNA nucleotides
DNA nucleotide structure
deoxyribose, phosphate group, nitrogenous base
RNA nucleotide structure
ribose, phosphate group, nitrogenous base
Nitrogenous bases in DNA
cytosine, guanine, adenine, thymine
Nitrogenous bases in RNA
cytosine, guanine, adenine, uracil
A-T bond number
2
C-G bond number
3
Purines
adenine, guanine
Pyrimidines
cytosine, thymine, uracil
DNA is…..
directional
What is a polynucleotide
single strand ?
DNA structure
double helix, two strands that run anti-parallel
How to identify three/five prime ends
five has the extra group
What holds the two strands of DNA together
hydrogen bonding
Diffusion
the net, passive movement of molecules from a region of high molecule concentration to a region of low molecule concentration, until equilibrium is achieved. It does not require energy.
When does diffusion stop
when the equilibrium is achieved
For diffusion, bigger SA:V ratio means
quicker diffusion
Facilitated diffusion
is the net movement of a substance through a plasma membrane via protein channels or protein carriers, from a region of high concentration to a region of low concentration
Important thing to remember about carrier/channel proteins in facilitated diffusion
each carrier only allows for certain substances to cross
Osmosis
net movement of water molecules across a semipermeable membrane from a region of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration)
Osmosis affects the ….. of a solution
tonicity
Hypertonic
high solute outside, osmosis out of cell
Hypotonic
low solute outside, osmosis into cell
Isotonic
no net osmosis
What happens when plant cells are in hypertonic
plasmolysis
Active transport
the net movement of dissolved substances into or out of cells against a concentration gradient, from an area of low substance concentration to an area of high substance concentration. It is an energy requiring process.
Reasons for active transport
allows us to maintain homeostasis, need greater amount than can be provided
Endocytosis
a process involving the entry of substances into the cell by the formation of a vesicle from the plasma membrane
Phagocytosis
bulk transport of solid particles.
Pinocytosis
bulk transport of liquids/fluids
Exocytosis
process of bulk transport of materials out of the cell through being secreted via a vesicle
What to use when protein vs waste exocytosis
protein is secreted, waste is expelled/voided
Plasma membrane
partially permeable boundary of a cell separating it from its physical surroundings.
Name of model
fluid mosaic model
Fluid mosaic model
phospholipid bilayer + proteins, antigens, cholesterol, self molecules
Substances that pass rapidly through lipid bilayer (gaps)
O2, CO2, water, amino acids, urea
Channel proteins
form aqueous pores allowing specific solutes to pass through the membrane
Carrier proteins
bind to solute and undergo a conformational change to transport the solute across the membrane. (if no energy is required, called facilitated diffusion).
Cytosol
fluid component of cell which consists mainly of water and dissolved substances. (excludes organelles + nucleus)
Cytoplasm
cytosol + organelles except the nucleus.
Protoplasm
cytosol + organelles + nucleus
Cytoskeleton
protein filaments that keep structure of cell
Parts of cytoskeleton
microfilaments, microtubules, intermediate filaments
Are cytoskeletons in prokaryotes
no
Cell walls found in
bacteria, plants, fungi
Nucleus
a membrane bound organelle containing the genetic material DNA. The control centre.
Structure of Nucleus
souble nuclear envelope that is porous, nucleolus inside, fluid inside, granules
Mitochondrion
site of aerobic respiration in eukaryotic organisms
Structure of mitochondrion
double membrane, cristae = folds, matrix fluid, own DNA, own ribosomes
Ribosomes
sites of protein production in cells in both prokaryotes and eukaryotes
Free ribosomes
produce ribosomes for use within cell
ER
organelle consisting of membrane bound channels
Rough ER
produces and transports proteins (for use outside of cells)
Smooth ER
produces and transports lipids for use outside of cell
Synthesis of protein for use outside of cell
produced in rough ER, transported via vesicle to golgi, where is is modified and packaged into vesicle which travels to cell membrane and fuses - protein is secreted
Golgi complex
organelle that packages material into vesicles for export from a cell
Other names for golgi complex
Golgi body, Golgi apparatus
Endosomes
digest products brought in via endocytosis
Lysosomes
break down unwanted particles in cell
Perioxomes
break down unwanted particles produced by metabolism
Cilia/flagella purpose
movement
Chloroplasts
chlorophyll-containing organelles that are responsible for photosynthesis in plant cells
Thykaloids
membrane structures in grana
Grana
membrane stacks that contain chlorophyll; site of light dependent stage in photosynthesis
Stroma
fluid in chloroplast
Types of junctions
occluding junctions, communicating junctions, anchoring junctions
Desmosomes
type of cell-to-cell junction in which protein filaments span the intercellular space and hold cells together.
Plasmodesmata
openings between plant cell walls through which adjacent cells are connected through cytoplasmic thread.
Plasmodesmata allows plants to
communicate cell to cell
Plastids
found in plants and protists
Centrioles
organise spindle fibres
Two pathways
mitochondrial pathway, death receptor pathway
Mitochondrial pathway
mitochondria signalled, breaks down, caspases ????
Death receptor pathway
lysosomes destroy them from outside of cell, caspases enter cell, breaks down, blebs, organelles break down, fragments phagocysed ?????
Types of variables in experiment
independent, dependent, control, extraneous
Other names for independent variable
experimental variable, tested variable
Controlled variables
variables that are deliberately kept constant during the course of the experiment
Extraneous/uncontrolled variables
variables in the experiment that may introduce errors to the results, typically caused due to faults in experimental design
Purpose of a control
as a comparison in order to see the effects of the independent variable
Why does repeating the experiment increase validity of results
reduces the effect of random error
Can a hypothesis be proven
no, only disproven.
Steps for an experiment
- Set up two groups - one control, one experimental
- Keep all other factors constant.
- How/when you are going to measure the independent variable
- Repeat the experiment many times.
Characteristics of living organisms
MRS GREN
MRS GREN stands for
Movement, Respiration, Sensitivity to stimuli, Growth and repair, Reproduction, Excretion, Nutrition
Organisation of life
atoms, molecules, organelles, cells, tissues, organs, organ systems, organism, population, community, ecosystem.
Prokaryote
cell that lacks membrane bound organelles
Eukaryote
cell that contains membrane bound organelles
Synchrotron
microscope used to examine molecules
Cell theory
all living organisms are composed of one or more cells, cells are the basic functional unit of life, all new cells arise from pre-existing cells
Five kingdoms
bacteria, animals, plants, protists, fungi
What polysaccharides are in the body?
Glycogen
Structure of chitin monomer
Glucose molecule with a nitrogen containing unit i.e. amino group
How much more energy per gram do lipids provide than glucose
Twice the energy
Where is fat stored
Adipose tissue
Function of cholesterol (TSFX)
Reduces membrane fluidity by reducing moderate temperature, but it also hiders solidification at low temperatures
All steroids start of as
Cholesterol
How many rings does a steroid molecule have
4
Purpose of glycolipids and glycoproteins
The act as self molecules for cell recognition
Key word to use for tertiary structure
‘Conformational’
What does repeating an experiment do
Reduce effect of random error, increase RELIABILITY of results
How to improve ACCURACY of results
Alter equipment
Two requirements of living organisms
Respiration, must be made of cells
Cyanobacteria do what
Photosynthesise
Lysosomes are found in both…
Plant and animal cells
Contractile vacuole
Contains a large amount of water and dissolved minerals and ions
What would happen if cells didn’t have a contractile vacuole
The cell would burst
What word must be used for diffusion, osmosis and facilitated diffusion definitions
Passive
What is the solution surrounding cells (between the cells and cell walls) after plasmolysis occurred in plant cell
Hypertonic solution
Salt solution will be accepted too for these cue cards
What are glycolipids
Lipids with a carbohydrate molecule attached
Where is chitin found
Fungi cell walls and exoskeletons of insects
What to remember about lipids in terms of monomers and polymers
Lipids have monomers but not polymers
What is an organelle that animals cellar have that plant cells don’t
Centriole
How tertiary structure holds together
hydrogen bonding, ionic interactions, covalent bonding (disulfide bridges), hydrophobic interactions (of R group)
