cell division and stem cells

what is an organelle

a sub-cellular structure in a cell

what is a cell

the building blocks of life that are made up of organelles

what is a tissue

groups of cells with a similar structure and functions

what is an organ

Groups of tissues with a similar function and structure, performing a function

what is an organ system

organs working together to perform a function

What is an organism

a living thing

the nucleus contains DNA in the form of ______

chromosomes

chromosomes contain a large number of ____

genes

Chromosomes are often made up of two______

chromatids

when two chromatids are joined together they are called a _______ pair of chromosomes

homolgous

what shape is a coil of DNA

double helix

chromosomes contain _____ _____ DNA

super coiled

how many chromosome pairs does an average human cell

23 pairs

Why is cell division needed

• growth

• replacement of cells

• repair of damaged tissue

what is the cell cycle

the life cycle of a cell. includes growing, copying DNA, and dividing 

what is the stage called when a cell isn’t dividing

interphase

equation for the length of time in a phase

observed number of cells at that time     X length of time in cell cycle

total number of cells observed

What are the stages of mitosis (in detail)

1. A cell has single chromatid chromosomes in its nucleus

2. chromosomes duplicate and condense to become visible

3. nuclear membrane breaks down and the chromosomes line up on the equator

4. spindle fibres attach to the chromosomes on the centromere and the chromosomes are  are pulled apart.

5. new nuclear membranes form around the two balls of chromosomes.

6. the cytoplasm splits (cytokinesis)

7. two new daughter cells are formed

What is a stem cell

A cell that is undifferentiated that can divide and differentiate to become specialised cells

during the early stages of an embryo are undifferentiated and can….

become any type of cell

how can stem cells be used

if a person has faulty or damaged cells, stem cells could be used to replace them.

what is therapeutic cloning

the nucleus of a patients cell is taken and swapped with the nucleus of an embryo cell. this created a pluripotent stem cell with the DNA of the patient. This stem cell then duplicates and is used to treat the patient as they will be able to differentiate into many types of cells and the cells wont be rejected.

what are issues with stem cells

• ethical and moral issues - many people are against using stem cells as they say it is preventing a human from growing and they relate it to an abortion.

• cancer - if the stem cells begin to divide uncontrollably, then they could form a tumour

• infection - when using adult stem cells, there is a chance that they carry infection. If these cells are then used then they could make a patients condition worse. also, if the stem cells are embryonic then the patient may need to take medication to stop them from being rejected, this makes the immune system more vunerable

Where are plant stem cells found

meristems

where are meristems found

at the tips of shoots and roots and in between xylem and phloem

what is special about plant stem cells

they retain there ability to differentiate throughout life, they can become any type of plant cell.

uses of plant stem cells

large numbers of genetically identical crops can be produced just for a small piece of plant tissue.