Biology Topic 2

Cell structure, Cell membranes and immune systems

What is the process of the cell cycle

A period of cell growth and DNA replication called the interphase and a period of cell division called mitosis. Interphase is divided into three separate growth stages. These are called G1, S and G2

What is the interphase

Preperation for division. Cells DNA is unravelled and replicated, to double its genetic content. The organelles are also replicsted to it has spare ones and its ATP production is increased.

G1 Phase

Cell grows larger, makes new proteins and performs its normal jobs. DNA synthesis.

S phase

Cell copied all of its DNA so each new cell will have a fulls set. Protein synthesis

G2 phase

Cell grows more, makes final parts needed for division and checks the DNA for mistakes. ATP stores increased Organelles are replicated

Mitosis definition``

Form of cell division that occurs during the cell cycle. In mitosis, a parent cell divides to produce two genetically identical daughter cells.

What is mitosis needed for in the body

Growth of multicellular organisms and for repairing damaged tissues.

What are the two strands of the chromosome joined in the middle by

Centromere

The separate strands are called ‘_______’

Chromatids.

How many different stages of mitosis are there?

4- Prophase, metaphase, anaphase and Telophase

Describe the basics of prophase

Chromosomes condense getting shorter and fatter and tiny bundles of protein called centrioles start moving to opposite ends of the cell forming a network of fibrous proteins called the spindle. The nuclear envelope breaks down and chromosomes lie free in the cytoplasm.

Describe the Metaphase

The chromosomes line up along the middle of the cell and become attached to the spindle by their centromere

Descirbe the Ananphase

Centromeres divide, seperating each pair of sister chromatids. The spindles contract, pulling chromatids to opposite poles of the spindle, centromere first.

Describe the Telophase Pt1

Chromatids reach the opposite poles on the spindle. They uncoil and become long and thin again. They’re now called chromosomes again. A nuclear envelope forms around each group of chromosomes so there are two nuclei

Describe the Telophase Pt2

The cytoplasm divides (cytokinesis) and there are now two daughter cells that are genetically identical to the original cell and to eachother.

How long does mitosis take

It varies but you can using numerical values.

How is mitosis linked to cancer

Normally when cells have divided enough times to make enough new cells they stop but if there is a mutation in a gene that controls cell division then the cells grow uncontrollably. Cells keep dividing which forms tumours.

How many micrometeres is one epu

2.5um

calculation for maginifcation

Mag=image size / actual size

Golgi apparatus function

process lipids and stores ribosomes. Also produces lysososmes

SER function

Store, synthesise and process lipids `

RER function

Synthesis and production of proteins. has several ribosomes onm the surface

Where are ribosomes made

Nucleolus

Mitochondria function

Respiration and atp production.

Ribosome Function

responsible for protein synthesis.

Homogulous definition

Two chromosomes one from each parent.Same length and centromere position

What is the interphase

Cells make a copy of its own chromosomes by replication of DNA. Cell grows and undertakes its normal fucntions.

What is the centromere

Constricted region of a chromosome that holds identical chromatids together after DNA replication

How is a chromosome formed

The DNA molecule winds around proteins called histones to form nucleosomes. They then supercoil to from a chromosome.

What are fungal cells made from

Chitin

What is the cristae

The folds inside the mitochondria and it increases the surface area and are studded with proteins for ATP production

What is defined as cancer

A group of cells that have lost the control of division. The body cannot recognise the additional cells that cant work normally.

What is the name for when cancer cells spread in the blood

Metastasis

Which tumours are cancerous

Malignant tumours they can divide rapidly and invade other tissues by metastasis.

What can bengin tumours do

divide at a normal rate, do not invade other tissues but they can disrupt organ functions.