Year 7 Science Assessment Task 3: Modules 3 and 4 Study Guide

Comprehensive practice flashcards in question-and-answer format covering Modules 3 and 4 for Year 7 Science, including cell biology, classification, adaptations, states of matter, properties of water, and Working Scientifically skills.

What are the three sections and mark distributions in the Year 7 Science Assessment Task 3 exam?

The exam is worth $50\,\text{marks}$ total: Section A consists of Multiple choice worth $10\,\text{marks}$, Section B consists of Short answer worth $25\,\text{marks}$, and Section C consists of Applying Science worth $15\,\text{marks}$.

What eight life processes are represented by the memory aid MRS C GREN?

Movement, Respiration, Sensitivity, Cellular structure, Growth, Reproduction, Excretion, and Nutrition.

How are living, non-living, and once-living objects differentiated?

Living objects currently carry out the life processes (e.g. a tree, bacterium, or dog); non-living objects have never been alive (e.g. a rock or glass cup); and once-living objects came from something that was alive but is no longer living (e.g. dead wood or a fallen leaf).

What are the three main ideas of cell theory?

1. All living things are made of one or more cells. 2. The cell is the basic unit of life. 3. All cells come from pre-existing cells.

What are the primary functions of the nucleus, cell membrane, mitochondria, and ribosomes?

The nucleus contains DNA and controls cell activities; the cell membrane is a selectively permeable boundary controlling what enters and leaves; mitochondria are the site of aerobic cellular respiration to release usable energy; and ribosomes make proteins (protein synthesis).

Which three structures are found in plant cells but not in typical animal cells?

A cellulose cell wall, chloroplasts in photosynthetic cells, and a large permanent vacuole.

Why do root hair cells generally lack chloroplasts?

Root hair cells are located underground and usually do not photosynthesise, so they generally have no chloroplasts.

How are red blood cells, muscle cells, and nerve cells structurally adapted to their functions?

Red blood cells have haemoglobin, a biconcave shape, and no nucleus to maximise space for oxygen carriage; muscle cells contain many mitochondria to supply energy for contraction; and nerve cells have long extensions to carry electrical messages over distances.

What is the correct sequence for the biological levels of organisation from simplest to most complex?

Cell $\rightarrow$ Tissue $\rightarrow$ Organ $\rightarrow$ Organ system $\rightarrow$ Organism.

What is the formula used to calculate magnification for a biological drawing?

$\text{Magnification} = \frac{\text{image size}}{\text{actual size}}$, ensuring both measurements are converted to the same units before dividing.

What is the word equation for photosynthesis, and in which organelle does it occur?

$\text{Carbon dioxide} + \text{water} \xrightarrow{\text{light energy, chlorophyll}} \text{glucose} + \text{oxygen}$; it occurs in the chloroplasts.

What is the word equation for aerobic cellular respiration, and where does it mainly take place?

$\text{Glucose} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water} + \text{energy}$; it occurs mainly in the mitochondria.

How is diffusion defined, and does it require energy from the cell?

Diffusion is the net movement of particles from an area of higher concentration to lower concentration, down a concentration gradient, until they are more evenly spread. It does not require the cell to use energy.

What are the levels of the classification hierarchy in order from broadest to most specific?

Kingdom $\rightarrow$ Phylum $\rightarrow$ Class $\rightarrow$ Order $\rightarrow$ Family $\rightarrow$ Genus $\rightarrow$ Species.

What are the naming conventions for a binomial scientific name?

A scientific name has two parts: Genus species. The genus starts with a capital letter, the species name starts with a lowercase letter, and both words are italicised when typed or underlined separately when handwritten.

On what three bases do Aboriginal and Torres Strait Islander Peoples classify living things?

Classification can be based on use (how a plant or animal is useful), form (its appearance or structure), and function (what it does or how it behaves).

What are the three types of adaptations, and what is an example of each?

Structural: a physical body feature (e.g. a camel's broad feet to walk on sand); Behavioural: a way an organism acts (e.g. a lizard basking in the sun); Physiological: an internal process or function (e.g. a kangaroo rat producing concentrated urine).

What chain of reasoning should be used to explain an adaptation in an examination?

Feature $\rightarrow$ how it works $\rightarrow$ survival advantage in that habitat.

How do particle arrangement, particle movement, shape, and volume compare across solids, liquids, and gases?

Solids: particles very close in regular arrangement, vibrate in fixed positions, fixed shape and fixed volume. Liquids: particles close in irregular arrangement, slide past each other, no fixed shape, fixed volume. Gases: particles far apart, move rapidly and randomly in all directions, no fixed shape or volume.

What are sublimation and deposition?

Sublimation is the direct change of state from solid to gas without becoming a liquid; deposition is the direct change of state from gas to solid without becoming a liquid.

Why does temperature remain constant along the flat sections of a heating curve?

A change of state is occurring, so energy is used to overcome attractions between particles rather than raise the temperature (increase kinetic energy).

What are the primary differences between evaporation and boiling?

Evaporation occurs only at the surface, can occur at temperatures below boiling point, is usually slower, and forms no bubbles. Boiling occurs throughout the liquid at the boiling point, forming gas bubbles throughout.

What is the formula and common units for density?

$\text{Density} = \frac{\text{mass}}{\text{volume}}$; common units are $\text{g/cm}^3$, $\text{g/mL}$, or $\text{kg/m}^3$, where $1\,\text{mL} = 1\,\text{cm}^3$.

What determines whether an object will float or sink in water?

An object with an average density less than water (about $1\,\text{g/cm}^3$) will float, whereas an object with an average density greater than water will sink. Alternatively, an object floats when the upward buoyant force balances its weight.

What is surface tension, and how does adding soap or detergent affect it?

Surface tension is the stretched-skin-like layer formed at water's surface due to water molecules attracting one another. Soap or detergent reduces surface tension, allowing water to spread and wet surfaces.

How is water displacement used to find the volume of an irregular solid?

Record the initial water volume, fully submerge the object, and record the final volume. The object's volume equals $\text{final volume} - \text{initial volume}$.

What are independent, dependent, and controlled variables in a fair test?

The independent variable (IV) is deliberately changed; the dependent variable (DV) is measured or observed; and controlled variables are kept constant to ensure a fair test.

In scientific investigations, how are validity, reliability, and accuracy defined?

Validity: whether the method tested what it was meant to test with all other variables controlled. Reliability: whether repeated trials yield similar results (improved by repeats and calculating means). Accuracy: how close measurements are to the true value (improved by calibrated equipment and careful technique).