B1-B4 Flashcards
Define: movement
An action by an organism or part of an organism causing a change of position or place
Define respiration
the chemical reactions in cells that break down nutrient molecules and release energy for metabolism
Define sensitivity
the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
Define growth
a permanent increase in size and dry mass by an increase in cell number or cell size or both
Define reproduction
the processes that make more of the same kind of organism
Define excretion
removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements
Define nutrition
taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds and ions and usually water
What are all living organisms made of?
Unicellular organisms, such as bacteria consist of a single cell
Multicellular organisms consist of many cells
Ex: humans = approximately 50 trillion cells
Draw and label the parts of a plant cell
Cellulose cell wall
Cell membrane
Nucleus
Cytoplasm
Motichondrion
Permanent vacuole
Chloroplast
Draw and label the parts of an animal cell
Cytoplasm
Nucleus
Cell membrane
Mitochondrion
Compare plant and animals cells
Plant cells -> cellulose cell wall outside the cell membrane
Animal cells -> no cell wall
Plant cells -> chloroplast (with chlorophyll)
Animal cells -> no chloroplast
Plant cells -> large vacuoles with cell sap
Animal cells -> small vacuoles
Plant cells -> starch grains
Animal cells -> no starch grains, sometimes glycogen granules
Plant cells -> regular shape
Animal cells -> irregular shape
What are the functions of the parts of the cell and animal cells?
Cell membrane:
Thin layer of protein and fat
Controls what goes in and out of cells
Partially permeable
Cell wall:
Plant cells only
Mainly cellulose (crisscrossed -> strong covering)
Protects and supports cells (no burst)
Fully permeable
Cytoplasm:
Clear jelly (around 70% water)
Many substances dissolved in it -> proteins
Different metabolic processes happen here
Vacuoles:
Space in a cell surround by a membrane, contain a solution
presses out -> keep cell shape
Plant cells -> large and permanent (solution of sugars + other = cell sap)
Animals cells -> smaller
Chloroplast:
Only in plants -> the green pigment (chlorophyll) -> photosynthesis
Often has starch
Nucleus:
Genetic information -> chromosomes -> DNA
What is the location and functions of these cells:
Ciliated cells
Root hair cells
Palisade mesophyll cells
Red blood cells
Sperm and egg cells
ciliated cells – in the trachea and bronchi →movement of mucus (carried bad bacteria and goes to stomach where acid destroys)
root hair cells – near the ends of plants roots → absorption
palisade mesophyll cells – beneath the epidermis of the leaf → photosynthesis
red blood cells – in mammal blood → transport of oxygen
sperm and egg cells – in testes and ovaries → reproduction
How is magnification calculated (formula)?
Magnification= size of image/size of real object
Define diffusion
Movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient as a result of their random movement
Passive processes -> no energy required
Diffuse until equilibrium is reached
What are factors that influence diffusion?
Surface area:
Surface area of membrane increase, rate of diffusion increases
More space for molecules to diffuse
Concentration:
Greater the concentration gradient, quicker the diffusion
Greater difference in concentrations
Temperature:
Temp increases, diffusion increases
Particles gain kinetic energy -> diffuse more quickly
Distance:
Shorter distance, faster diffusion
Substance travels less
What quality does the membrane have to have to allow diffusion?
It is partially permeable
Define osmosis
Movement of water molecules from region of higher water potential to region of lower water potential through a permeable membrane
What is the effect on plant tissue if it is immersed into solutions of different concentration?
Low concentration solution (high water potential):
Solution in cell more concentrated than outside cell
Water diffuses for equilibrium
Vacuole is full -> pressing up against cell membrane+wall -> cell is turgid (as it should be)
Equal concentration solution (equilibrium):
Solution outside and inside cell have equal concentration
Cell is flaccid -> plant begins to wilt
High concentration solution (low water potential):
Solution inside cell less concentrated than outside cell
Water diffuses out for equilibrium -> cytoplasm and vacuole shrink -> cell wall left as cytoplasm pulls away -> cell wall is plasmolysed (plasmolysis)
What process is necessary for the uptake of water in plants?
Osmosis
Soil has water -> water diffused through the cell membranes of root hair cells -> into plant -> photosynthesis + retain turgidity
What is the effect on animal cells if it is immersed into solutions of different concentration?
Low concentration solution:
Solution outside is less concentrated than inside
Water diffuses in -> no cell wall -> cell ruptures due to excess water -> lysis
Equal concentration solution:
Normal
High concentration solution:
Solution outside is more concentrated than inside
Water diffuses out -> cytoplasm shrinks -> whole cell shrivels -> crenation
What is are the chemical elements in carbohydrates?
Carbon, hydrogen and oxygen
What are carbohydrates? (+bond type)
Long chains of simples sugars
Glucose -> simple sugar (monosaccharide -> soluble in water)
2 glucose -> maltose (disaccharide -> soluble in water)
Lots of glucose -> starch, glycogen, cellulose (poly saccharide -> insoluble in water)
Carbohydrates bonds -> glycosidic bonds
What is the used of carbohydrates?
Easily available energy
Release energy into cells -> respiration
Glucose travels to cells to release energy for metabolic reactions
Storage as starch in plants + cellulose fibers in plant walls
What is are the chemical elements of proteins?
Carbon, Hydrogen, Oxygen, Nitrogen, small amounts of Sulphur
What are proteins? (And type of bond)
Long chains of amino acids
20 different types that can be arranged many ways
Amino acids joined by peptide bonds-> protein
Some are soluble (haemoglobin) some are insoluble (keratin)
What are the uses of proteins?
Making cells
Enzymes
Haemoglobin, keratin, etc.
What are the chemical elements of fats/lipids?
Carbon, hydrogen, oxygen
What are fat/lipids?
Triglycerides (1 glycerol, 3 fatty acids)
Insoluble in water
What are the uses of fats/lipids?
Storage of energy
Insulation
Making cell membranes
What test can be preformed to confirm the presence of starch?
Iodine solution
Dimple tray -> samples of food (large surface area) -> add one drop of iodine solution
Orange/brown -> negative
Blue/black -> positive
What test can be preformed to confirm the presence of reducing sugars?
Benedict’s solution
Mash food (high surface area) -> add equal amounts of food and Benedict’s solution -> heat in water bath
Blue -> negative
Green/orange/red -> low/medium/high amounts
What test can be preformed to confirm the presence of proteins?
Biuret test
Chop food into small pieces (large surface area) -> add biuret solution to food -> shake until you see color
Blue -> positive
Purple -> negative
What test can be preformed to confirm the presence of fats and oils?
Ethanol emulsion
Chop up food (more surface area) to around 1 cm^3 -> add 2cm^3 of ethanol -> shake -> add 3cm^3 of water (1:2:3 ratio)-> shake
Milky/white -> positive
Clear -> negative
Fat dissolves in ethanol but not water -> fat-ethanol mixture separates from water if fat is present
Why is water important for metabolic reaction?
Water is a solvent
we are 60% water
All reactants must be dissolved in water for metabolic reactions
For transport all molecules have to be dissolved in water
What are enzymes?
Biological catalyst that speed up chemical reactions inside all cells -> not used up in the process
Catalyst -> speed up reactions by lowering the activation energy
Occur naturally
Thousands of types, all for different reactions
Enzymes -> proteins
Explain enzyme action (complementary shapes)
Enzymes -> very specific about which reactions they can catalyze
Molecules have to be exactly the right shape to bind with enzyme + react
Active site (part of enzyme with a specific shape in order to bind to correct substrate/products) need to be the right shape for substrate (reactant) to attach
What effects the rate of a enzyme-catalyzed reaction?
Temp, pH, enzyme concentration, substrate concentration, surface area, pressure
What effect does a change in temp or pH have on an enzyme?
change from the optimum (37°C, pH 7-> when enzyme works the fastest) causes the shape of the enzyme to change permanently -> the enzyme is denatured
TEMP
Chemical reactions work faster at high temps -> more likely to collide -> reaction more likely to occur
BUT
Enzymes are damaged by high temps -> for humans around 40°C
- enzymes lose shape, active site no longer fits -> denatured
pH
pH too acidic or alkaline-> denature
REMEMBER: enzymes are chemical not organisms- they are not KILLED but DENATURED
