Additional Science (Route 2): Unit 5 Flashcards
Draw and label a human cell
What are the functions of these parts of a cell?
Nucleus
Cytoplasm
Cell membrane
Nucleus – contains DNA and controls the activities of the cell
Cytoplasm – where most of the chemical reactions occur
Cell membrane – controls the passage of substances in and out of the cell
What are the functions of these parts of a cell?
Mitochondria
Ribosomes
Mitochondria – where energy is released from respiration
Ribosomes – where protein synthesis occurs
Draw and label a plant cell
What are the functions of these parts of a cell?
Cell wall
Chloroplasts
Permanent vacuole
Cell wall – strengthens the cell
Chloroplasts – absorb light energy to make food via photosynthesis
Vacuole – filled with cell sap and provides a store of water
What do the vacuoles of plant cells contain?
Cell sap
What controls the chemical reactions inside cells?
Enzymes
What is diffusion and where does it happen?
Diffusion is the net spreading out of particles of a gas (or substance in a solution) from [high] to [low]
Diffusion occurs in the lungs – this is how oxygen is moves into the blood
What affects the rate of diffusion?
Temperature and the [concentration] difference effects the rate of diffusion
What is osmosis and where does it occur?
Water often moves via osmosis – the water particles move from a net [high] to a [low] across a partially permeable membrane
Osmosis occurs in the root hair cells
What happens to a plant cell if you put it in highly salty water?
In salty water there is a [low] of water – this means water moves out of the cell (from [high] to [low]) and the cell will shrink and become flaccid
What happens to a plant cell if you put it in pure water?
In pure water there is a [high] of water resulting in water moving into the cell (from [high] to [low]) and the cell will fill of water and become turgid
Draw a picture of a red blood cell and explain how it is specialised
Draw a picture of a nerve cell and explain how it is specialised
Draw a picture of a cilia cell and explain how it is specialised
Draw a picture of a root hair cell and explain how it is specialised
Draw a picture of a guard cell and explain how it is specialised
Draw a picture of villi in the small intestine and explain how it is specialised
What is the equation for photosynthesis?
Light
6CO2 + 6H2O → C6H12O6 + 602
Why is energy needed for photosynthesis and how does a plant obtain this energy?
Energy is needed to convert carbon dioxide and water into sugar (glucose)
The energy is light energy – this is trapped by the chlorophyll in the chloroplasts
What can affect the rate of photosynthesis?
Temperature
Carbon dioxide levels
Light intensity
What is a limiting factor and what can these be in photosynthesis?
A limiting factor is anything, which prevents a process from continuing to increase
In photosynthesis there are: -
Low temperature
Shortage of CO2
Shortage of light
What is the glucose produced by photosynthesis used for?
Used for respiration
Stored as starch
How do plants store glucose?
Insoluble starch
What minerals do plants need for healthy growth?
Nitrates and magnesium are needed for healthy growth of a plant
Why do plants need nitrates and magnesium?
Nitrates – needed to produce amino acids (used to form proteins)
Magnesium – for chlorophyll production
How can you tell if a plant is deficient in the following?
Nitrates
Magnesium
Nitrates – stunted growth (no proteins)
Magnesium – yellow leaves (no chlorophyll)
What is the energy source for most communities of living organisms?
Radiation from the Sun
What do plants compete for?
What do animals compete for?
Plants – light; water; nutrients (from soil)
Animals – food; mates; territory
Where is DNA carried in most cells?
In the nucleus
What is a quadrat and how is it used?
A quadrat is a square frame enclosing a known area (e.g. 1m2) to measure the numbers of organisms in an area
What are transects and how are they used?
Transects are lines to identify how distributed across an area an organism is
*Collect data along line / use quadrats
What are bacteria?
Bacteria are single-celled microorganisms (which lack a nucleus)
What are yeast?
Yeast are single celled organisms
What are tissues, organs and organ systems?
Similar cells are organized into tissues (cells which work together to complete a certain function)
Organs are a group of different tissues working to perform a function
Organ systems are organs which work together to complete a function
What are the main parts of the digestive system?
Draw and label an atom
What are the masses and charges of these parts of an atom?
Proton
Neutron
Electron
Protons = +ve
(mass 1)
Neutrons = neutral
(mass 1)
Electrons = -ve
(mass 1/2000th)
Why do atoms usually have no overall electrical charge?
Atoms usually have no overall charge because they have equal numbers of protons (+ve) and electrons (-ve), which cancel one another out
All atoms of a particular element (e.g. carbon) all have the same number of what?
Protons
What are the following numbers called?
a = relative atomic mass
b = atomic number
What do the numbers tell you about the atom?
a = relative atomic mass – the number of protons and neutrons in the atom
b = atomic number – the number of protons (usually the same as the number of electrons)
What is an alloy and why are they used?
Give some examples
Alloys are mixtures of metals with other elements, e.g. iron + carbon → steel
They have a combination of properties, e.g. bronze, brass, steel etc…
What is a smart alloy and why are they used (shape-memory)?
Give some examples
Smart alloys can return to their original shape after being deformed – e.g. glasses and braces
What do these terms means: -
Element
Compound
Mixture
Element – pure substance with only 1 type of atom (e.g. gold)
Compound – 2 or more elements chemically bound (e.g. carbon dioxide)
Mixture – more than 1 element or compound not chemically bound (e.g. air)
What are the symbols for the following atoms: -
Oxygen, Nitrogen, Chlorine, Hydrogen, Sodium, Copper, Potassium, Helium, Calcium, Zinc, Iron, and Carbon
Oxygen (O), Nitrogen (N), Chlorine (Cl), Hydrogen (H), Sodium (Na),
Copper (Cu), Potassium (K), Helium (He), Calcium (Ca), Zinc (Zn), Iron (Fe), and
Carbon (C)
What happens to atoms when they chemically react to form a compound?
They share, give away, or take electrons
What are the names of these compounds, and which atoms are found in them?
H2O
CaCO3
H2SO4
HCl
CO2
Water (H2O)
Calcium carbonate (CaCO3)
Sulfuric acid (H2SO4)
Hydrochloric acid (HCl)
Carbon dioxide (CO2)
What is an isotope?
An isotope is an atom with a different amount of neutrons
Use the periodic table to draw the electron structure of the following: -
Neon
Calcium
Sodium
How can you tell which group these atoms are in?
The number of electrons in the outer shell is the same as their group number
How many electrons can occupy the 1st and 2nd shell (energy level) of an atom?
2 in the 1st shell and 8 in the 2nd shell
The electron structure of sodium can be represented as 2,8,1 – what does this mean?
Represent these atoms: -
Fluorine
Oxygen
Potassium
Magnesium
2,8,1 means 2 electrons in the 1st shell, 8 electrons in the 2nd shell and 1 electron in the 3rd shell
Fluorine = 2,7
Oxygen = 2,6
Potassium = 2,8,8,1
Magnesium = 2,8,2
Define these terms: -
Element
Compound
Mixture
Element – a pure substance made from 1 type of atom only
Compound – 2 or more elements chemically bound
Mixture – 2 or more elements or compounds mixed together which are not chemically bound
What happens to the electrons of 2 atoms when they chemically react?
During a chemical reaction electrons are either given away, taken, or shared
What is an ion?
How are +ve ions formed?
How are -ve ions formed?
An ion is an atom with a charge
+ve ions have lost electrons
-ve ions have gained electrons
Explain how the following atoms become ions (will they be +ve or –ve)?
Potassium
Magnesium
Chlorine
Oxygen
Potassium – loses 1 electron (K+)
Magnesium – loses 2 electrons (Mg2+)
Chlorine – gains 1 electron (Cl-)
Oxygen – gains 2 electrons (O2-)
Use diagrams to show how these atoms for ionic bonds: -
Sodium + Chlorine
Describe and use a diagram to show the structure of ionic compounds
Ionic compounds have a giant structure – they are bonded to 6 other ions by electrostatic bonds
What are the melting and boiling points of ionic compounds like?
Why is this?
Ionic compounds have high melting points and boiling points – to melt them you have to supply enough energy to break the 6 bonds attached to each ion
What happens to the electrons when atoms form ionic bonds and covalent bonds?
Which is the strongest?
Ionic bonds – 1 atom loses electrons and another gains electrons
Covalent bonds – electrons are shared
An individual covalent bond is stronger than an ionic bond
Use diagrams to show how the following compounds are formed: -
Hydrogen
Oxygen
Hydrogen Chloride
Use a diagram to show how water is formed
What are the melting and boiling points of covalent compounds like?
Explain why this is
Covalent compounds have low melting and boiling points (are often gases) are there is no attraction between the molecules
How are the elements of the periodic table arranged?
What are the rows called?
What are the columns called?
Elements are arranged in order of atomic number
Rows are called periods
Columns are called groups
Which 2 elements would be out of order in the periodic table if they were arranged by atomic mass instead of atomic number?
Potassium and Argon
Why do elements in the same group have similar properties?
Elements in the same group have similar properties as they all have the same number of electrons in their outer shell
What do these symbols mean?
(s)
(l)
(g)
(aq)
(s) = solid
(l) = liquid
(g) = gas
(aq) = aqueous
What are the symbols for these compounds?
Calcium carbonate
Sodium chloride
Hydrochloric acid
Calcium carbonate – CaCO3
Sodium chloride – NaCl
Hydrochloric acid - HCl
Why do covalent compounds not conduct electricity when dissolved?
Covalent compounds do not conduct because they do no break down into ions
Give the names of 3 covalent compounds which have giant ionic structures?
What is the structure of each like?
Diamond – 4 carbon-carbon covalent bonds
Graphite – 3 carbon-carbon covalent bonds
Silicon dioxide – 2 double silicon-oxygen covalent bonds
Why does graphite conduct electricity?
Graphite conducts electricity because it is only bonded 3x (meaning there is a delocalised electron to pass the charge)