cell biology- topic 1

What is the role of the nucleus in a cell?

Contains genetic material which controls the activities of the cell

Ribosomes

Synthesise proteins from amino acids

Mitochondria

Release energy from glucose through aerobic respiration

Cytoplasm

Where the chemical reaction occurs

Chloroplasts

Absorbs sunlight for photosynthesis

Cell membrane

Controls what enters and leaves the cell

Cell wall

Strengthens the cell giving it structure and support made of cellulose

Vacuole

Contains the cell sap

Prokaryotic

Smaller simpler e.g bacteria (no nucleus)

Magnification equation

IAM magnification = image/actual

Eukaryotic

Complex - plants + animals

What plant parts are visible under light microscope

Cell wall, nucleus, cytoplasm

Why can’t you see ribosomes under light microscopes

Too small - microscope’s magnification and resolution isnt high enough

Which part of the microscope is used to increase resolution

The focusing wheel (coarse adjustment knob and fine adjustment knob)

Which is used to increase magnification

Change to a higher powered objective lense

How are root hair cells adapted

Large SA and thin walls for absorption of water and mineral ions

How are red blood cells adapted

No nucleus, lots of haemoglobin, thin and and biconcave shape

How are nerve cells adapted

Long axon - cover more distance, axon is insulated, many branches - connect to other nerve cells

How are muscle cells adapted

Lots of mitochondria - generate energy, long - space to contract

How are sperm cells adapted

Lots of mitochondria, Tail - swim to egg, carries enzymes to digest through egg

Stem cells

Unspecialised cells which differentiate to become certain types of specialised cells

Where are stem cells

Embryo, adult bone marrow, meristem tissue(tip of plant root)

Stem cells use

Repair damaged tissue, replace damaged cells

Stages of the cell cycle

1)cell growth- increase him off organelles and duplicate DNA

2)mitosis- chromosomes line up in pairs then separate, nucleus divides

3) cell membrane and nucleus divide

Purpose of mitosis

Growth and repair

Products of mitosis

2 genetically identical daughter cells

Diffusion

The movement of particles from a high to low concentration

Osmosis

The movement of water from a high to low concentration through a partially permeable membrane

3 bio e.g. of diffusion

O2 into blood from alveoli

CO2 out of blood into alveoli

Glucose out of blood into cells

Active transport

The movement of particles from a low to high concentration using energy against a concentration gradient