What is a microscope used for in science?
To make very small objects appear much larger for study.
What does a compound light microscope use to magnify objects?
Multiple lenses.
Which scientist used a compound light microscope to see cells?
Robert Hooke.
What does an electron microscope use for magnification?
Electrons.
What can an electron microscope see that a compound light microscope cannot?
Viruses and tiny cell structures.
What are the main parts of a light microscope?
Eyepiece lens, objective lens, stage, coarse focus knob, fine focus knob, arm, base, light source, and stage clips.
How should you carry a microscope when setting it up?
By holding the arm and base.
What is the first step to focus a microscope?
Begin with the lowest-power objective lens.
How do you calculate total magnification of a microscope?
Multiply eyepiece magnification by objective-lens magnification.
What happens to the field of view as magnification increases?
The field of view decreases.
What happens to image detail as magnification increases?
The image becomes more detailed.
What is a cell in biology?
The basic building block and unit of life.
What does cell theory state about the composition of living things?
All living things are made of one or more cells.
According to cell theory, where do all cells come from?
All cells come from pre-existing cells.
How does organisation progress in multicellular organisms?
From cells to tissues, organs, organ systems, then the complete organism.
What defines a unicellular organism?
It consists of only one cell performing all life functions.
What does the plasma membrane control in a cell?
It controls what enters and leaves the cell.
What is the permeability characteristic of the plasma membrane?
It is selectively permeable, allowing only certain molecules to pass.
What does the nucleus contain and control?
It contains genetic material and controls cell activities.
What is the function of ribosomes in a cell?
They make proteins needed for cell growth and repair.
What role do mitochondria play in the cell?
They release energy through respiration.
What are the functions of the endoplasmic reticulum?
It transports materials and helps make proteins and lipids.
Which structures do plant cells usually have that animal cells lack?
Plant cells usually have a cell wall, chloroplasts, and a large vacuole.
What distinguishes fungal cells from plant and animal cells?
Fungal cells have a cell wall and vacuoles but no chloroplasts.
What defines a specialised cell?
It is adapted for a specific function by shape, organelles, or structures.
Which muscle type is voluntary and moves the body?
Skeletal muscle.
Where is cardiac muscle found and what is unique about it?
Only in the heart and rich in mitochondria.
Why do mature red blood cells lack a nucleus?
To provide more space for oxygen-carrying haemoglobin.
How do root hair cells absorb water and minerals?
Using a large surface area and thin cell wall.
How do guard cells control stomata?
By swelling and shrinking to open and close them.
What do xylem cells transport and how?
Water and minerals through hollow, thick-walled tubes.
What do phloem cells transport and how?
Sugars through long tubes with sieve-like ends.
What is homeostasis in the body?
Maintenance of a stable internal environment.
What is the correct order of organs in the digestive tract?
Mouth, oesophagus, stomach, small intestine, large intestine, rectum.
Which organ supports digestion by producing bile?
The liver.
What does physical digestion do to food?
Breaks food into smaller pieces and increases surface area.
How does chemical digestion break down food?
Uses enzymes to break large molecules into smaller ones.
Which enzyme breaks down starch?
Amylase.
What is the role of the kidneys in excretion?
Filter blood, remove wastes, control water and salt levels, and produce urine.
What do the bladder and urethra do in the excretory system?
The bladder stores urine and the urethra carries it out of the body.
What does the central nervous system consist of?
The brain and spinal cord.
What are the main parts of a neuron?
Dendrites, a cell body, an axon, and axon terminals.
What allows electrical messages to travel quickly in a neuron?
Its long axon.
What do sensory neurons do?
They carry messages from receptors to the central nervous system.
What do motor neurons do?
They carry messages from the brain or spinal cord to muscles or glands.
What is the general path of information in the nervous system?
From stimulus to receptor, sensory neurone, central nervous system, motor neurone, and response.
How does the nervous system transmit signals compared to the endocrine system?
The nervous system uses fast electrical impulses with short-term effects, while the endocrine system uses slower hormones with longer-lasting effects.
What is an organ transplant?
A procedure replacing a damaged organ with a healthy donor organ.
What causes organ rejection after transplantation?
The immune system attacking the transplanted organ as foreign.
Why do transplant recipients take immunosuppressant drugs?
To reduce immune responses that cause organ rejection.
What does dialysis do when kidneys fail?
It filters blood and removes waste and excess water.
Does dialysis fully replace kidney function?
No, it does not fully replace kidney function.
How do natural organs differ from artificial replacements?
Natural organs are efficient, self-controlled, and can self-repair.
What are some ethical issues in organ transplantation?
Organ shortages, donor consent, fair access, and donor risks.
Test your knowledge with 30 questions on Cells and Body Systems.
1. What is the primary purpose of a microscope?
2. Which statement correctly distinguishes a compound light microscope from an electron microscope?
Review the complete course in the revision sheet for Cells and Body Systems.
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