Science Assessment 2 Year 7

What are international symbols used for in chemistry?

To ensure consistency and understanding worldwide for elements, regardless of language.

What is a compound?

A substance made of two or more different types of atoms chemically bonded together.

What is the difference between pure substances and mixtures?

Pure substances consist of only one type of particle, while mixtures contain multiple types of particles that are not chemically bonded.

What are the two types of pure substances?

Elements and compounds.

What do elements consist of at the particle level?

Identical atoms of one type, which can exist as individual atoms or as molecules.

What is the primary function of the nucleus in a cell?

Controls the cell’s activities and contains genetic material (DNA).

What role do mitochondria play in a cell?

They are the 'powerhouse' of the cell, producing energy through cellular respiration.

What is the main distinction between plant and animal cells regarding vacuoles?

Plant cells have a large, central vacuole, while animal cells typically have smaller vacuoles.

What is photosynthesis?

The process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight.

What is cellular respiration?

The process of breaking down glucose and oxygen to produce carbon dioxide, water, and energy.

What characterizes unicellular organisms?

They are made of a single cell that performs all life processes.

What is the significance of classification in biology?

It helps organize living things based on their similarities and differences, aiding in understanding relationships and diversity.

What are the characteristics of living things summarized as MRS GREN?

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

What defines a vertebrate?

An animal with a backbone.

What does ectothermic mean?

Animals whose body temperature changes with the environment.

What is a dichotomous key?

A tool used to identify organisms through a series of yes/no questions.

What are balanced forces?

Forces acting on an object that are equal and opposite, resulting in no change in motion.

What is the unit of force?

Newton (N).

What causes friction?

The contact force that occurs when two surfaces rub against each other.

What are unbalanced forces?

Forces that are not equal, causing a change in an object's motion.

What happens to mixtures compared to pure substances?

Mixtures can have their components separated by physical methods, while pure substances cannot.

What are organelles?

Specialized structures within cells that perform specific functions.

How do plant cells differ from animal cells in terms of cell structure?

Plant cells have a cell wall and chloroplasts, whereas animal cells only have a cell membrane.

What is the role of chloroplasts in plant cells?

They contain chlorophyll and help in the process of photosynthesis.

What are compounds characterized by at the particle level?

Molecules that contain two or more different types of atoms chemically bonded in a fixed ratio.

What is the difference between unicellular and multicellular organisms?

Unicellular organisms consist of a single cell; multicellular organisms consist of many cells that function together.

What is the significance of the vacuole in plant cells?

It stores water, nutrients, and waste products, helping maintain structure.

What is an endoskeleton?

An internal skeleton made of bones or cartilage.

What is the process of asexual reproduction in unicellular organisms?

Cell division (mitosis), where one cell splits into two identical cells.

What type of force occurs without contact between objects?

Forces that act at a distance, such as gravity.

What is a resultant force?

The overall force acting on an object when more than one force is applied.

How do scientists classify living things?

By grouping them based on structural features and habitats.

What is the chemical equation for photosynthesis?

Carbon dioxide + water → glucose + oxygen.

What distinguishes a mixture from a compound?

In a mixture, components are physically combined, not chemically bonded.

What does the term 'endothermic' refer to?

Animals that can regulate their own body temperature.

What does the term 'unbalanced force' indicate?

A force that causes a change in an object's motion.

What is meant by 'sensitivity' in the characteristics of living things?

The ability to sense and respond to the environment.

What does the term 'exoskeleton' refer to?

A hard outer covering that protects the body.

What is the purpose of a dichotomous key in biology?

To provide a systematic method for identifying organisms.

What is the result of balanced forces acting on an object?

The object does not change its motion.

What is the function of the cell membrane?

It controls what goes in and out of the cell.

What is the effect of friction on motion?

It slows down or stops an object’s motion.