Cells and cell cycle

Cell theory

1. All organisms are composed of one or more cells

2. Cells are the basic functional unit of all living things

3. All cells come from pre-existing cells

Centrioles

Cell division

sER

Makes lipids

rER

Makes proteins

Ribosomes

Protein synthesis

Golgi

Packages proteins

Lysomes

Digest molecules and old cell parts, contain enzymes

Proteinsysnthestis

Nucleus, Ribosomes, rER, Golgi, Membrane

Why do we use standard form?

Less cumbersome and reduce chance of data errors

Resolution

Smallest distance between two objects that can be detected by a microscope

Light microscope

Look at living organisms, no smaller than nanometers

Erythrocytes

Red blood cell have no nucleus so more space for hemoglobin

Bi-concave shape so more surface area

Neuron

Axon is long cytoplasm, nerve pulses transmitted to extremities by 1 cell

Myelin sheath surrounds axon and acts as insulator

Squamous epithelial cells

Permeable for easy diffusion

Single layer of flat cells which reduces diffusion pathway

Sperm cells

Flagellum to swim faster

Extra mitochondria which produces ATP

Ova cell

Jelly coat that allows speed through but protects ova

Purpose of cell division

growth of new tissues

Repair of damaged tissues

Produce gametes

Mitosis stages

Split of the nucleus

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis - split of cell and cytoplasm

Cell cycle

G1 - growth

S - synthesis, DNA replication

G2 - growth and mitosis prep

M - mitosis

Checkpoints

1. End of G1, Check if big enough and have proper proteins if not go to G0 until ready

2. During synthesis check if DNA replicated

3. During mitosis phase, checks if complete

Interphase

Stage that’s always proceeds mitosis when DNA is replicated

Prophase

Chromosomes become visible and nuclear envelope disappears

Metaphase

Chromosomes arrange themselves at centre of cell

Anaphase

Each of the 2 chromatid migrates to opposite poles

Telophase

Nuclear envelope reforms bad produces 2 daughter cells

Simple diffusion

Small molecules such as oxygen or Co2

Channel protein

Facilitated diffusion

Down conc grad

Glucose amino acids, charged ions

Carrier protein

Active transport

Low to high

Requires energy

Co-transport

Active transports with two molecules

If opposite direction no ATP needed

Aquaporin

Osmosis

Water high to low