Free Grade 7 Science and Technology Exam Flashcards

A cellulose cell wall, chloroplasts and a large permanent vacuole are typical plant-cell features. Both have a membrane, cytoplasm and usually a nucleus. Root cells generally lack chloroplasts: not every plant cell photosynthesises.

The two separated spots show that X contains at least two dye components under these conditions. A single spot alone would not prove purity: some components may travel together or be invisible.

Read eastings first, then northings: 23.4 east and 56.7 north in the grid’s kilometre numbering. It identifies a 100 m square inside square 2356, not an exact point. Latitude and longitude use a different coordinate system.

The ovule becomes a seed, containing the developing embryo; the ovary develops into a fruit. Fertilisation joins a male gamete with the egg cell inside an ovule. Pollination is the earlier transfer of pollen to a stigma.

Iron is needed for haemoglobin, while vitamin B12 supports normal red-blood-cell formation. Deficiency of either can cause anaemia, but tiredness has many possible causes. Assessment and treatment depend on the cause; do not assume everyone needs iron.

No. Arteries carry blood away from the heart; veins return it. In the usual adult pulmonary circuit, pulmonary arteries carry oxygen-poor blood to the lungs and pulmonary veins return oxygen-rich blood.

Red blood cells transport oxygen using haemoglobin; white blood cells contribute to defence; platelets help blood clot. Plasma is the liquid carrying these components and dissolved substances. Blood therefore has several functions, not oxygen transport alone.

Kidney → ureter → bladder → urethra. Ureters carry urine to the bladder; the bladder stores it; the urethra carries it out. Urine does not normally flow through the blood vessels that enter and leave the kidney.

No. Excretion removes metabolic wastes, such as urea in urine and carbon dioxide through the lungs. Egestion removes undigested material as faeces. The urinary system is important in excretion but is not the only route.

Moist-heat cooking uses water or steam, as in boiling, stewing and steaming. Dry-heat methods include baking, roasting and frying. This classification includes frying despite its liquid oil; use adult supervision around hot equipment.

Bacteria are single cells without a membrane-bound nucleus. Fungi have eukaryotic cells and obtain nutrients from organic material. Viruses are acellular and reproduce only using host cells. Some microbes are useful; not all cause disease.

Iodine is needed to make thyroid hormones. Inadequate iodine can contribute to goitre, an enlarged thyroid, but enlargement has other causes too. A health professional assesses it; do not take iodine supplements solely because a neck looks swollen.

School examples include stimulating drinks such as tea, nourishing drinks such as milk, and refreshing drinks such as water. These groups may overlap. Read ingredients and sugar information: even unsweetened fruit juice contains free sugars.

Freezing slows or stops much microbial growth while food remains frozen, but it does not reliably destroy all microbes. Thawing can allow growth again. Bottling requires a tested food-specific process; simply boiling and sealing any food is unsafe.

Gas particles have much more space between them, so their volume can decrease substantially. Liquid particles are already close together; water compresses only slightly. Use a clean, needle-free classroom model under teacher supervision.

No. About 100 °C applies at standard atmospheric pressure. Lower air pressure at higher altitude lowers the boiling point. Compare substances at the same pressure; boiling temperature alone does not show that water is safe to drink.

Protons and neutrons are in the nucleus; electrons occupy regions around it. Their relative charges are +1, 0 and −1 respectively. A neutral atom has equal numbers of protons and electrons.

No. Stored chemical energy is transferred electrically and then to light and thermal energy. Energy is conserved overall, although some transfers are less useful for the intended task. Energy and power are different quantities.

Moving water turns a turbine connected to a generator, converting mechanical energy into electrical energy. Water is renewed through the water cycle, but electricity output depends on water availability and the installation’s operating conditions.

Yes. Static friction between a shoe and the ground helps a person push forward without slipping. Friction opposes relative sliding or its tendency at the contact; it does not always point opposite the object’s overall motion.

Pressure = normal force ÷ area = 120 ÷ 0.30 = 400 Pa. One pascal equals one newton per square metre. For the same force, spreading the load over a larger area reduces the average pressure.

Radiation: electromagnetic waves transfer energy without needing matter between the source and receiver. Conduction transfers heat through interactions in matter; convection transfers heat with the bulk movement of a fluid.

Rubbing can transfer electrons, leaving a charge imbalance. The charged balloon can polarise nearby neutral paper, producing attraction. The paper need not initially carry an opposite net charge.

The other branch still has a complete circuit and can remain lit. In a simple series circuit, opening the single path stops current through both lamps. This describes a low-voltage classroom circuit, not work on mains wiring.

No. Iron and many steels are strongly attracted, but metals such as copper and aluminium are not strongly attracted by an ordinary magnet. Some stainless steels are also weakly attracted or not noticeably attracted.

Ideal mechanical advantage = effort arm ÷ load arm = 0.60 ÷ 0.20 = 3. This assumes perpendicular forces and an ideal rigid lever. A smaller effort requires a greater effort distance; the lever does not create energy.

A fixed pulley mainly changes the pull direction and has ideal mechanical advantage 1. Two supporting rope segments can give a movable pulley ideal mechanical advantage 2. Real friction and pulley weight reduce the benefit.

Frequency = vibrations ÷ time = 12 ÷ 3 = 4 Hz. One hertz is one cycle per second. Frequency differs from amplitude, which measures the size of the disturbance.

Crust → mantle → outer core → inner core. The outer core is liquid and the inner core is solid. The mantle is mainly solid rock that can flow slowly over geological timescales, not a global liquid ocean.

Igneous rock forms as magma or lava cools. Sedimentary rock forms through processes such as deposition, compaction and cementation. Metamorphic rock forms when existing rock changes under heat and pressure without completely melting.

Breaking down in place is weathering. Transport of the fragments is erosion. Deposition occurs when transported material is laid down. Weathering can be physical, chemical or biological; the three processes are related but distinct.

It records the duration of sufficiently bright sunshine, usually by a burn trace on a calibrated card. A thermometer measures temperature and a rain gauge measures rainfall. Sunshine duration is not the same as total daylight duration.

They absorb and emit some outgoing infrared radiation, slowing energy loss to space. The natural greenhouse effect keeps Earth warmer; increasing greenhouse gases changes the energy balance. This differs from a glass greenhouse’s restricted airflow.

Earth turns approximately 360° in 24 hours: 15° per hour. Therefore 30° corresponds to 2 hours of solar time; places farther east reach local solar noon earlier. Official clock times follow political time-zone rules.

Energy and material pass from grass to the grasshopper that eats it, then to the bird. Always check the diagram’s arrow key. The arrow convention is not an instruction about which way the predator moves.

A parasite lives on or in a host and obtains resources at its expense. A symptom such as poor feeding can have many causes, including unsuitable water conditions. Observation alone rarely identifies the cause; seek competent fisheries advice rather than choosing a chemical treatment.

Rotation is Earth’s spin, producing day and night over about 24 hours. Revolution is its orbit around the Sun, taking about 365¼ days. Seasons result mainly from Earth’s tilted axis as it orbits, not simply from changing distance to the Sun.

It supplies food and can provide income and employment through crops, livestock and related products or services. Benefits depend on access to land, water, markets and suitable management; agriculture does not guarantee a profitable harvest.

Weathering supplies mineral particles; decomposed organic material and living organisms also contribute. Over time, horizons can develop: topsoil above subsoil and less-weathered parent material. Air and water occupy pores. Real profiles vary, and topsoil is not always dark.

Texture describes the relative amounts of sand, silt and clay. Structure describes how soil particles form aggregates. Both affect aeration, infiltration and root growth; clay-rich soil is not automatically infertile or always poorly drained.

No. Fertility concerns the supply of essential nutrients, but plant growth also depends on suitable pH, water, air, structure and other conditions. Organic matter can support soil functions; nutrient additions should respond to actual needs.

Rainfall, temperature, frost, soil, slope, pests, available labour and management can differ. A crop must suit its environment. Yield differences alone do not identify one cause; compare conditions before drawing a conclusion.

A harrow breaks clods and levels a seedbed; a ridger forms raised rows; a rotovator cultivates using rotating blades; a grass trimmer cuts vegetation. Cleaning and safe storage help preserve equipment. Learners should identify tools, not operate powered machinery without qualified supervision.

Abrasives can damage the protective tin coating and expose the metal beneath. Wash with a suitable mild detergent, rinse and dry. Damaged food-contact utensils need an adult’s assessment; polishing cannot make every damaged utensil safe.

Keeping other relevant conditions comparable helps test the effect of water. Record measurements, repeat observations and report limitations. Evidence can support a hypothesis, but one successful experiment does not automatically turn it into a scientific law.

It adds the numeric values in B2, B3, B4 and B5: a range of four cells. A colon marks a continuous range. The formula does not add the cell addresses themselves.

2. AVERAGE includes the numeric zero but ignores the blank and text in referenced cells: (4 + 0) ÷ 2 = 2. It does not divide by all four cell positions.

Use a clear title, readable text size, strong text–background contrast and a few concise points. Format selected text consistently. A slide supports an explanation; dense paragraphs and unnecessary animation can hide its main message.

To names the main recipient; Cc sends a visible copy; Subject describes the message. Check recipients and content before sending. Follow school and provider age rules, and ask a trusted adult before sharing personal information.

Use safe water, clean hands, clean utensils and sound fruit washed appropriately; follow the teacher’s recipe and measure ingredients accurately. Keep perishables chilled. Fresh juice is not sterile, and tasting cannot establish food safety.