States of Matter, Cells, Forces, and Energy Concepts

Three states of matter

Solid, liquid, gas

Property

A characteristic or attribute of a substance

Properties of solids

Definite shape and volume; incompressible

Properties of liquids

Definite volume but no definite shape; slightly compressible

Properties of gases

No definite shape or volume; highly compressible

Arrangement of particles in a solid

Particles are closely packed together in a fixed position

Arrangement of particles in a liquid

Particles are close together but can move past each other

Arrangement of particles in a gas

Particles are far apart and move freely

What holds the particles in a solid together?

Strong intermolecular forces

What holds the particles in a liquid together?

Weaker intermolecular forces than in solids

How do the particles in a solid move?

They vibrate in place

Process of solids turning to liquids

Melting

Process of liquids turning to solids

Freezing

Melting point of a substance

The temperature at which it changes from solid to liquid

Process of liquids turning to gases

Evaporation or boiling

Process of gases turning to liquids

Condensation

Boiling point of a substance

The temperature at which it changes from liquid to gas

Types of substances that melt at a specific temperature

Pure substances

Types of substances that melt over a range of temperatures

Mixtures

What happens when salt is added to water and stirred?

Salt dissolves in water

What is formed when a solid dissolves in a liquid?

A solution

What do we call the solid that dissolves in a liquid?

Solute

What do we call the liquid that a solid dissolves into?

Solvent

What is an insoluble solid?

A solid that does not dissolve in a liquid

What is a soluble solid?

A solid that dissolves in a liquid

Effect of increasing the temperature on solubility

Generally increases solubility

Word to describe how easily a solute dissolves

Solubility

What is a saturated solution?

A solution that cannot dissolve any more solute at a given temperature

How do we separate an insoluble solid mixed with a liquid?

Filtration

What is the liquid left in the conical flask after filtration called?

Filtrate

What is the solid left in the filter paper after filtration called?

Residue

Equipment needed for filtration

Filter paper and a funnel

How do we separate a soluble solid from a liquid?

Evaporation

How do we separate two liquids that are mixed together?

Distillation

How do we separate the dyes in ink?

Chromatography

What is an organism?

A living entity that can function independently

What is a cell?

The basic structural and functional unit of life

What is an organelle?

A specialized subunit within a cell that has a specific function

Organelle that holds the DNA and controls the cell's activities

Nucleus

Layer around the cell that controls what enters or leaves the cell

Cell membrane

Gel-like substance where most chemical reactions take place in a cell

Cytoplasm

Small organelle that performs respiration

Mitochondria

Purpose of cells performing respiration

To produce energy

Rigid layer that strengthens a cell and supports its shape

Cell wall

Small organelle that performs photosynthesis

Chloroplast

Three organelles found in plant cells, but not animal cells

Chloroplasts, cell wall, large central vacuole

Five organelles present in both animal and plant cells

Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes

What do we use to look at things too small for the naked eye?

Microscope

Three main steps needed for looking at something through a microscope

Place the slide, adjust the focus, observe

What happens when we focus a microscope?

The image becomes clearer

What does magnification mean?

The process of enlarging the appearance of an object

Word to describe how big something really is

Actual size

Word to describe how big something looks through a microscope

Apparent size

Equation to work out image size

Image size = actual size × magnification

What is a specialised cell?

A cell that has adapted to perform a specific function

Two specialised animal cells

Red blood cell, muscle cell

Function of the red blood cell

To carry oxygen

Two adaptations of the red blood cell

Biconcave shape, no nucleus

Why does a red blood cell have no nucleus?

To maximize space for hemoglobin

Why does a red blood cell have a biconcave shape?

To increase surface area for oxygen absorption

Function of the muscle cell

To contract and enable movement

One adaptation of a muscle cell

Contains many mitochondria for energy

Why do muscle cells have lots of mitochondria?

To provide energy for contraction

Two examples of specialised cells in plants

Root hair cell, xylem cell

Function of a root hair cell

To absorb water and nutrients from the soil

Two ways in which a root hair cell is specialised to its function

Large surface area, thin cell wall

Why do root hair cells have large extensions?

To increase surface area for absorption

Why do root hair cells not have any chloroplasts?

They are not involved in photosynthesis

What is an area of high concentration?

A region where the number of particles is greater

What is an area of low concentration?

A region where the number of particles is fewer

What is diffusion?

The movement of particles from an area of high concentration to an area of low concentration

Three factors that affect diffusion in cells

Temperature, concentration gradient, surface area

Concentration gradient

The size of the difference in concentration between two places.

Rate of diffusion

Affected by concentration gradient, temperature, and cell surface area.

Contact force

A force that requires contact between two objects.

Non-contact force

A force that does not require contact between two objects.

Resultant force

The overall force acting on an object after all forces are combined.

Extension

The increase in length of an object when a force is applied.

Compression

The decrease in length of an object when a force is applied.

Hooke's law

The principle that states the force needed to extend or compress a spring is proportional to the distance it is stretched or compressed.

Energy store

A system that holds energy in various forms.

Power

The rate at which energy is transferred or converted.

Law of conservation of energy

Energy cannot be created or destroyed, only transformed from one form to another.

Fossil fuels

Energy sources formed from the remains of ancient organisms over millions of years.

Renewable energy source

An energy source that can be replenished naturally over time.

Tissue

A group of cells that work together to perform a specific function.

Organ

A structure made up of different tissues that work together to perform a specific function.

Organ system

A group of organs that work together to perform complex functions.

Enzyme

A protein that acts as a catalyst to speed up chemical reactions in the body.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed.

Element

A pure substance that cannot be broken down into simpler substances by chemical means.

Compound

A substance formed when two or more elements are chemically bonded together.

Mixture

A combination of two or more substances that are not chemically bonded.

Chromosome

A structure within cells that contains DNA and genetic information.

Heredity

The passing of traits from parents to offspring.

Chromosome

A structure within cells that contains DNA.

Variation

Differences in characteristics among individuals.

Genetic variation

Differences in DNA sequences among individuals.

Environmental variation

Differences in traits caused by environmental factors.

Genetically identical

Organisms that have the same genetic makeup as their parents.