Prelims (Mod 1-4) Flashcards
organic chemicals
biomacromolecules
based on carbon, hydrogen, and oxygen, many are polymers made by joining many smaller molecules
carbohydrates
lipids
nucleic acids (nitrogen and phosphorus)
proteins (nitrogen and maybe sulfur)
use of carbon dioxide and oxygen in cell
reactants and products in biochemical processes
use of mineral salts in cell
co-enzymes that help enzymes speed chemical reactions
Cl and Na ions needed for cell membrane function, nerve, muscle cell functioning
calcium salts needed for bones and teeth
iron needed for red blood cells
use of water in cell
transport medium for substances inc ell
solvent, substances dissolve in it
reactant and product in chemical processes
inorganic chemicals
water: hydrogren and oxygen
mineral salts (ions): K+, Cl-
Carbon dioxide: carbon and oxygen
function of lipids
used as a way to store excess energy
all cell membrane are built from lipids
can be broken down and used in respiration to produce energy
lipids
carbon, hydrogren, oxygen
fats and oils
1 glycerol molecule + 3 fatty acid chains
contains more than twice the energy of carbohydrates
carbohydrates
carbon, hydrogren, oxygen
sugars, starch and others
monosaccharides= glucose
disaccharides= sucrose (table sugar)
polysaccharides= (many) starch, glycogen (made by animals to store sugar), cellulose
uses of carbohydrates
sugars: energy chemical, fuel for cellular respiration (ATP)
starch & glycogen: polymer molecules used to store sugar as food reserve
cellulose & lignin; polymers of sugar used structurally by plants
nucleic acids
2 types: DNA and RNA
basic unit: nucleotide
DNA: deoxyribonucleic acid, genetic information stored in chromosomes, controls cell functions and organism characteristics
RNA: ribonuleic acid, needed for protein synthesis
DNA is polymer of sugars, phosphate, nitrogen bases in double helix shape
function of proteins in chemicals in cells
needed for body growth and repair
e.g. ezymes, hormones
proteins
main structral chemical of organelles
polymers made from amino acid molecules chained together
most abundant organic molecule in the shell
head of phospholipid bilayer
hydrophilic phosphate head
tails of phospholipid bilayer
hydrophobic fatty acid tails
fluid mosaic model
describes the cell membrane as a double layer of lipids, a lipid bilayer, with the ability to flow and change shape, like a two-dimensional fluid. Specialised protein molecules are
embedded in the lipid in various patterns like a mosaic. Both proteins and phospholipids help to control the exchange of materials
between the external and internal environments.
where is cholesterol located on the cell membrane
interspersed among the phospholipid molecules in animal cells. This makes the membrane more flexible.
membrane proteins
adhesion, transport, recognition, receptor
adhesion protein
link cells together and help maintain the organism’s three-dimensional structure.
transport protein
passageways that allow specific substances to move across the membrane.
recognition proteins
or glycoproteins are made up of a protein molecule with a
carbohydrate molecule attached. These proteins identify the cell and are called antigens or marker
molecules. They allow the immune system to distinguish between foreign particles (‘non-self’) and the body’s own (‘self’) cells.
receptor protein
cause the cells to respond only to certain signals from substances such as hormones that bind to them, giving them specific functions.
What goes in and out of a cell
in: glucose, water, salts, oxygen
out: urea, carbon dioxide, water, salts
what does permeability depend on
molecules size, electrical charge, lipid solubility
diffusion
net movement of molecules from a region of high concentration to a region of low concentration of that substance, until equilibrium is reached
what influences th rate of diffusion
heat since kinetic energy makes the particles move more, temperature can slow or speed the rate
examples of simple diffusion
oxygen and carbondioxide
facilitated diffusion
large molecules (glucose or amino acids) or charged particles (ions) trequire certain proteins called
carrier proteins and channel proteins in the cell membrane to assist them in diffusing into the cell.
how does the cell membrane diffuse large molecules over
carrier proteins
how do ions diffuse over cell membrane
channel proteins
osmosis
the process by which water moves through the cell membrane
the movement of water molecules through a semi-permeable membrane from a region of high water concentration to a region of low water concentration
dilute solution
contains a small amount of solute in relation to the amount of water and the water is said to be in high
concentration.
a solution of 1% salt/sugar
has the same water and salt/sugar concentration as an average cell
hypertonic
higher salt/sugar concentration and a lower water concetration than a cell
hypotonic
lower salt/sugar concentration and a higher water concentration than a cell
isotonic
same salt/sugar concentration and the same water concentration as a cell
animal cells when surrounding solution is hypotonic
haemolysis (swells and bursts)
animal cells when surrounding solution is hypertonic
shrinks
plant cell when surrounding solution is hypotonic
turgid
plat cells when surrounding solution is hypertonic
plasmolysis
active transport
movement of molecules from a region of low concentration to a region of high
concentration, and requires the input of energy. against concentration gradient
requires a carrier protein that spans the membrane to actively move chemicals from a low to a high concentration, utilising cellular energy
endocytosis
When a large particle has to be moved into a cell, the cell membrane can change its shape to surround the particle and engulf it
requires energy
phagocytosis
if solid particle is engulfed by cell membrane
pinocytosis
when liquid is engulfed by cell membrane
exocytosis
process by which these substances are transported to the external
environment of the cell. in an membrane vesicle
requires energy
factors affecting exchange of materials across membrane
chemical factors (being soluble in lipid), physical factors (size of particle), concentration gradient, SA:V ratio
high SA:V ratio
smaller cell has more surface area in relation to its volume
low SA:V ratio
A larger cell has a smaller amount of surface area in relation to its volume
function of carbohydrates
sources of quick energy, break down to glucose and convert into energy in respiration process
function of lipids?
used as a way to store excess energy
all cell membrane are built from lipids and proteins
what does denatured me?
when a protein’s shape alters when heated too much or wrong pH environment
use of carbon dioxide and oxygen in cell
reactants and products in biochemical processes
use of carbon dioxide and oxygen in cell
reactants and products in biochemical processes
use of carbon dioxide and oxygen in cell
reactants and products in biochemical processes
what are the two stages of photosynthesis and what are their main products
light dependent stage( hydrogen) and light-independent stage (glucose)
cholesterol and phytosterols
(in animals) or (in plants) provide some flexibility to the membrane.
what makes the rate of diffusion quicker
higher temperature and steeper concentration gradient
where is the recognition protein
pheriperal membrane
where are transport proteins
transmembrane
where are adhesion proteins
transmembrane
where are receptor proteins
transmembrane
cellular wastes
CO2: from CR, eliminated through respiratory system
Urea (nitrogenous waste: from digestion of proteins, eliminated by excretory system
Lactic acid: from anaerobic respiration (fermentation of acid), eliminated by liver
Hydrogen peroxide: from metabolic processes, eliminated by peroxisomes
Ethanol (alcohol): from fermentation in yeast and plants, eliminated by diffusion
Hydrogen sulfide: anaerobic cellular respiration (prokaryotes), eliminated by diffusion
photosynthesis equation
Carbon dioxide + water → oxygen + glucose +ATP
Cellular respiration equation
Oxygen + glucose → carbon dioxide + water + ATP
CR waste product
Carbon dioxide
Photosynthesis waste product
oxygen
Types of CR
Aerobic: presence of oxygen, complete breakdown of glucose, more ATP
Anaaerboic: absence of oxygen, partial breakdown of glucose, less ATP
Enzymes
Protein molecules that control metabolic reactions, act as biological catalysts
Production of enzymes
Present in the cytoplasm of a cell, produced by ribosomes
Composition of enzymes
Globular proteins, consisting long chains of amino acids folded into specific shape
Polypeptide chain (consisting of amino acids)
Contains specific active site and catalyses a distinct chemical reaction
Molecule on which enzyme acts is called substrate
Types of enzyme reactions
Anabolic reaction: combining of two simpler substances to form more complex substances
Catabolic reaction: the breakdown of large, complex substances into smaller simpler ones
Example of an anabolic and catabolic reaction
Anabolic: photosynthesis making glucose
Catabolic: cellular respiration breaking glucose down
Two types of models to describe how enzymes work
Lock and key model: the active site of the unbound enzyme is precise in shape to the substrate
Induced fit model: the enzyme changes shape on contact with the substrate. When the substrate (or its products) is released the enzyme returns to its original form/shape.
Factors affecting enzyme activity
Temperature
Enzyme have an optimal temperature
Becoming too hot or to cold: denaturation
Denaturation: active site changes shape so the substrate can no longer bind
pH
The optional pH is different for different types of enzymes depending on their environment
In body optimal pH between 6-8
Enzyme activity can decrease further from optimum pH
The pH changes bonds that give enzyme its 3D tertiary structure
bonds become disrupted and shape of enzyme changes
Substrate concentration
Number of reactions is limited to number of available enzymes
The substrate concentration increase, the chemical reaction will increase, more substrate becoming occupied by free enzymes
When concentration is higher than of enzymes, rate of reaction can no longer increase (point of saturation), no effect if all active sites are occupied
Multicellular organism
Require system for nutrients and waste removal
Different cells specialise to perform different functions
characteristics that enable them to overcome the problems of their large overall size
- Each cell which makes up the multicellular organism is itself very small.
- Each cell in the multicellular organism has a specialised structure and function.
- Many cells work together in a coordinated fashion to keep the organism alive.
- The multicellular organism has a longer lifespan than a unicellular organism.
Unicellular organisms
Using diffusion, osmosis and active transport to take nutrients and remove waste through cell membrane
Colonial organisms
Individual cells living in a colony
Individually carry out metabolic functions
Simple specialised cells within the colonial organisms can improve efficiency of overall functioning
Importance of specialised cells
Each cell cannot perform every function (MRS GREN) in order for organism to survive
This would be waste of nutrients, energy and processes would be slower
Increases efficiency and utilisation of biological resources
Location of stem cells
In the embryo (embryonic stem cells)
In the human brain and bone marrow (adult stem cells)
Plants → In meristematic tissue, young growing regions like roots, shoot tips
Red blood cell structure, function, relationship between the two
Flat disk/doughnut shape, which is round with an indentation in the centre, but isnt hollow
Lacking nucleus
To carry oxygen to cells and carbon dioxide away from cells/tissues
Disc shaped- fits more easily through small capillaries. No nucleus to free up space to hold more oxygen. Many mitochondria to power the movement around bloodstream
No nucleus allows change in shape and move through body easier
Root hair cells structure, function and relationship between the two
Long tubular shaped outgrowths from root epidermal cells
To absorb water and nutrients from the surrounding soil
The projection of the root hair increases the SA over which water can be absorbed by the roots
Squamous cells in Alveoli structure function and relationship between the two
Large, flattened cells
Smooth surface
Lines internal organs, protecting them by secreting lubricating fluid
Secrets lubricating substance in heart
Oxgyen and CO2 must diffuse across the cells of the alveoli into the lungs
Single layer of flattened cells make up the alveoli walls- this reduced the distance over which the gases have to diffuse, hence diffusion is faster
Palisade cells in leaf tissue structure, function and relationship between the two
Cells are packed tightly together and contain chloroplasts
Contains largest number of chloroplasts per cell
Chloroplasts in the palisade cells is the site of photosynthesis
Being close together maximise light absorption
Many chloroplasts help maximise energy transfer, conversion of light to chemical energy
The palisade cells are round in upper layer of the lead which is the layer exposed to sunlight. This enables the leaf to make the most of sunlight failing on its surface.
Examples of hierarchy of multicellular organisms
Mitochondria → cell → cardiac muscle tissue → ventricular muscle heart → circulatory system → human
Axon → motor neutron → motor nerve → sympathetic nervous system → nervous system → frog
Chloroplast → spongy cell → spongy mesophyll → leaf → foliage → tree
Beta cell → pancreatic tissue → pancreas → endocrine system → organism
Organic substances
glucose, amino acids, fatty acids, glycerol, nucleotides, vitamins
Inorganic substances
phosphates, sodium, chloride ions, and water
Autotrophs
organisms that can produce their own organic nutrients and need to obtain water, mineral ions and the gases carbon dioxide and oxygen from external sources (producers)
Vascular autotrophs
Plants with a transport system for support and movement of substances
Non-vascular autotrophs
Without a transport system providing support or moving substances
osmosis and diffusion is used to receive and eliminate wastes
Heterotrophs
organisms that cannot produce their own food, services its nutrition from other sources (consumers)
3 organs of a plant
Shoot, root, vascular systems
4 types of tissues in plants
meristematic, dermal, vascular, ground tissue
meristematic tissue
found?, function
Found at the tips of roots and shoots
Function: Cells divide in meristematic tissue to produce new cells and therefore growth
Cell differentiation can also take place to produce specialised cells
Dermal tissue
function
Function: protects the plant tissues from damage and controls interactions with the plant’s surroundings
Dermal tissue
Epidermis layer
definition, function
Epidermal layer is the outermost layer of the dermal tissue
Secretes a waxy layer called the cuticle (reduces water loss from plant)
vascular tissue
function, main types
Function: Transport of substances around the plant
Found in roots, stem and leaves
Xylem: transports water and mineral salts from roots to the leaves
Phloem: transports sucrose (glucose from PS) around the plant
Ground tissue
definition, features
All of the internal cells of a plant other than the vascular tissue
Is bulk of the plant tissue
Different cell types specialised for food storage, support and photosynthesis.
Adaptive radation
Where one species diversifies into many different species as they moe into new areas with differing selection pressures.
Natural selection
Stpes of process
- Varation in the population
- Overproduction of species (competition)
- Selection pressure and selection
- Reproduction (survive to reproduce)
- Adaption
Marco evolution
change in an species over milliions of years
Micro evolution
change in species over some generations and a much shorter period of time