Term 1 Flashcards
biological science
observation, identification, experimental investigation and theoretical explanation of natural phenomena
the cell theory
- all living things are composed of cells and substances produced by cells or developed out of cells
- basic functional units of organisms
- must be in a constant environment to efficiently obtain nutrients and excrete wastes
- all cells come from pre existing cells
- all cells contain genetic material which is passed on to daughter cells
labelled microscope
check book
total magnification formula
eye piece magnification x objective lens magnification
field of view
the area you see > the diameter of the area you will see with no objective lens
10x/22?
10 = eye piece magnification 22 = field number
how many micrometres in a millimetre
1000
millimetres
10^-3
micrometres
10^6
field of view under high power formula
diameter (HP) = [diameter (LP) x magnification (LP)]/ magnification (HP)
the higher the magnification, the ___ (higher/lower) the field of view
lower
cell membrane
- selectively permeable barrier that controls movement in and out of the cell
- 7.5 nm in width
- bilipid (two sheets of polar phospholipids)
some substances pass through easier than others because they are ____ (larger/smaller)
smaller
the cell membrane has phospholipids with hydro___ heads and hydro___ tails
philic
phobic
diffusion
- passive transport
- the process by which substances move from an area of high concentration to low, down the concentration gradient (the difference in the concentrations)
- no energy used
equilibrium (diffusion)
when substances are equally distributed
simple diffusion
free and unaided movement of molecules through the cell membrane down their concentration gradient
facilitated diffusion
globular proteins move molecules through the cell membrane down their concentration gradient
osmosis
the diffusion of water across a semi-permeable membrane down its concentration gradient
active transport
cellular energy is used to move molecules against their concentration gradient
exocytosis
active transport out of the cell
endocytosis
active transport into the cell
two types of endocytosis
phagocytosis and pinocytosis
phagocytosis
takes in larger substances (e.g. bacteria)
pinocytosis
takes in fluids and solute
surface area
the area of outer surface on an object
volume
3D space inside an object
as an object gets larger, SA:V gets ____ (larger/smaller)
smaller
the bigger the cell, the ____ (bigger/smaller) the volume and the ____ (more/less) nutrients needed and wastes produced
bigger
more
a ____ (larger/smaller) SA:V ratio is more desirable (and why)
larger
- allow enough nutrients and wastes through the membrane and keep it functioning efficiently
when a cell grows, its volume increases at a ____ (greater/less) rate than its surface area and so the SA:V ____ (decreases/increases)
greater
decreases
cells
- basic building blocks of all living things
- provide structure for the body
- take in nutrients and convert them into energy
- carry out specialized functions
prokaryotes
unicellular organisms (microorganisms)
e.g. of prokaryotic cells
amoeba, unicellular fungi, bacteria, protozoa, unicellular yeasts, unicellular algae, paramecium
eukaryotes
multicellular organisms
- all organisms are made of 2 or more cells and they need all parts to survive
levels of organisation
cells > tissues > organs > organ systems > organisms
features of a prokaryotic cell
- pre nucleus
- most primitive cells- smallest and simplest
- neither nucleus nor membrane bound organelles (but has a cell membrane)
- single cell with DNA
- lacks a nucleus and organelles
- smaller (0.5-2um)
- the only organisms for 2 billion years)
- have a cell wall covered by a capsule
- frail cytoskeleton that aides movement
- some have a flagella and pilus
- only organelle is ribosomes in cytoplasm
- unicellular
features of a eukaryotic cell
- true nucleus
- first cells to appear on Earth with internal compartments (organelles)
- nucleus surrounded by cytosol (cytoplasm)
- complex cytoskeleton
- larger (10um) and more complex
- contains nucleus and membrane-bound organelles
organelles
- minute subcellular structures with particular functions
- organs of cells
e.g. of eukaryotic cells
animals cells, plant cells, and some protists
cell wall
- protects the cell and gives it shape
- made of cellulose
- found in plants, algae, fungi, and most bacteria
cell membrane
- outer covering, protective layer around all cells
- for cells with cell walls, the membrane is inside
- allows food, oxygen and water into the cell and waste products out of the cell
cytoplasm
- gelatin-like inside cell membrane that constantly flows
- aka protoplasm
chloroplasts
- convert light energy of the Sun into sugars to be used by cells
- photosynthesis depends on the chlorophyll (green pigment) molecules in the chloroplasts
- two membranes
vacuoles
temporary storage spaces for food, water and waste
nucleus
- directs all cell activities and contains instructions for everything the cell does
- these instructions are found on DNA (hereditary material)
- usually the largest organelle
mitochondria
- double membrane celled organelles that release energy from food by breaking down food into carbon dioxide
- metabolize or breakdown carbohydrates and fatty acids to generate energy
- eukaryotic cells use energy in the form of a chemical molecule called ATP (adenosine triphosphate)
- the powerhouse because they release energy from food
- double membrane celled organelle
- synthesize proteins for their own use
- inner membrane is folded to form a series of cristae (shelves) which increases the SA of the membrane
- spherical - high SA:V ratio for the efficient uptake and release of materials
endoplasmic reticulum
- series of folded membranes that move proteins around in a cell
- like a conveyor belt
- two types - smooth and rough
- flattened membrane bound sacs called cisternae
smooth ER
- responsible for the synthesis and transport of lipids and steroids
- ribosomes not attached
rough ER
- ribosomes attached
- responsible for the synthesis of proteins
golgi bodies
- stacked flattened membranes
- sort and package proteins
lysosomes
- the purpose is to digest things - food or breaking down the cell when it dies
- break down food molecules, cell wastes, and worn out cell parts
nucleolus
makes ribosomes > make proteins
which organelle contains its own DNA?
nucleus
what is the relationship between the ER and golgi apparatus?
the golgi sorts and packages proteins and the ER moves them
what structures are found in plants but not animal cells
cell wall, central vacuole, chloroplasts
enzyme
- produced in living cells
- catalysts that speed up reactions in organisms
active site
- portion of an enzyme in contact with substrate
substrate
- a substance that attaches to enzyme active site
catalyst
a chemical that causes a chemical change (but isn’t altered by the reaction) and speeds up the reaction
lock and key model
- at active sites, enzyme has specific geometric shape and orientation that a complementary substrate fits into perfectly
induced fit model
when an enzyme binds to appropriate substrate, subtle changes in the active site occur- enhances catalysis as the enzyme converts substrate to product
photosynthesis
the method by which most autotrophs make their food i.e. obtain energy and store it as chemical energy
the process whereby radiant energy from the Sun is converted to the chemical bond energy of glucose
photosynthesis formula (word form)
carbon dioxide + water > glucose + oxygen
arrow = sunlight + chlorophyll
photosynthesis formula
6CO2 + 6H20 > C6H12O6 + 6O2
stoma
open space inside a chloroplast
thylakoid
contains green chlorophyll, that absorbs light
grana
stacks of thylakoid
two types of photosynthesis reactions
light and dark
photosynthesis process
- light hits chlorophyll and an electron from the molecule gets excited
- chloroplast holds chlorophyll in a protein complex called the reaction centre, allows the electron to be ejected and used to drive photosynthesis
factors affecting photosynthesis
- light
- temperature
- CO2
- chlorophyll
- H2O
when a process depends on more than one factor…
the rate of that process is limited by the factor that is in the shortest supply
as the intensity of the light or carbon dioxide increases (individually), the rate of photosynthesis ___ (increases/decreases), until _ ___ __ ____. At this point it is further limited by other factors.
increases
it reaches its limit
as the temperature increases, the rate of photosynthesis ____ (increases/decreases), until the _____. From that point, when temperature increases, rate ____ (increases/decreases), until it eventually ___.
increases
maximum
decreases
stops
what happens during a light reaction
ADP + light energy > ATP
H2O > H + O2
what happens during a dark reaction
CO2 + H > sugars
ATP > ADP + energy
in which part of the cell does glycolysis occur?
cytoplasm
in which part of the cell does Kreb’s cycle occur?
mitochondria
in which part of the cell does electron transport chain occur?
mitochondria
how many molecules of ATP are produced during glycolysis?
2
the absence or presence of which substance determines what pathway the molecule pyruvate proceeds down?
oxygen
aerobic respiration
efficient production of energy, requiring oxygen to occur
- involves Kreb’s Cycle and ETC
- produces large amounts of ATP (34-36) from each glucose molecule
- mitochondria
- products = waste products and water
anaerobic respiration
not as efficient method of producing small amounts of energy, without the involvement of oxygen
- involves glycolysis (splitting of glucose)
- occurs in cytoplasm
- for each molecule of glucose, 2 ATP are produced rapidly
- followed by fermentation into either lactic acid or ethanol
- used only if there is not enough O2 for aerobic respiration
- can be useful for rapid rate of release of energy
waste products produced during cellular respiration
lactic acid, ethanol, CO2, H2O
overview of cellular respiration
- a glucose molecule enters cell
- glycolysis > produces 2 molecules of ATP and 2 of CO2
- forms pyruvate - different paths based on presence of oxygen
anaerobic: pyruvate undergoes process of fermentation forms ethanol (in plants and fungi) forms lactic (in animals) ENDS HERE
aerobic: pyruvate is converted to Acetyl CoA
overview of cellular respiration
- a glucose molecule enters cell
- glycolysis > produces 2 molecules of ATP and 2 of CO2
- forms pyruvate - different paths based on presence of oxygen
anaerobic: pyruvate undergoes process of fermentation forms ethanol (in plants and fungi) forms lactic (in animals) ENDS HERE
aerobic: pyruvate is converted to Acetyl CoA
4. Kreb’s Cycle > produces 2 molecules of ATP and 4 of CO2
5. Electron Transport Chain > produces 32-34 molecules of ATP
6. H2O + waste products
overview of cellular respiration
- a glucose molecule enters cell
(in cytoplasm)
- glycolysis > produces 2 molecules of ATP and 2 of CO2
- forms pyruvate - different paths based on presence of oxygen
anaerobic: pyruvate undergoes process of fermentation forms ethanol (in plants and fungi) forms lactic (in animals) ENDS HERE
(in mitochondria)
aerobic: pyruvate is converted to Acetyl CoA
4. Kreb’s Cycle > produces 2 molecules of ATP and 4 of CO2
5. Electron Transport Chain > produces 32-34 molecules of ATP
(out)
6. H2O + waste products
cellular respiration
process of turning glucose into energy rich ATP molecules, that occur at any set time
cellular respiration
- glycolysis
- kreb’s cycle
- electron chain transport
