Cells and Control Flashcards
How do you do a scientific drawing?
Use a sharp pencil
Use clear, unbroken lines
Draw outlines of the main features - no shading
Take up at least half of the space
Keep parts in proportion
Label important features with straight, uncrossing lines
Include a scale and the magnification
What is a chromosome?
They are coiled up lengths of DNA molecules that contain genetic material. Cells normally have two copies of each chromosome, making them ‘diploid’ cells. One chromosome comes from the organism’s ‘mother’; one comes from its ‘father’.
What is mitosis used for?
Growth or repairing damaged cells.
What is mitosis?
A type of cell division and part of the cell cycle resulting in two daughter cells with identical chromosomes to the parent cell
What is interphase?
The time when a cell is not dividing, where chromosomes are uncoiled. The cell replicates all of its subcellular structures and DNA in this period
What are the four stages of mitosis?
Prophase, metaphase, anaphase, telophase
What is prophase?
The first stage of mitosis, where chromosomes condense, getting shorter and fatter. The nucleus membrane breaks down and chromosomes lie free
What is metaphase?
The second stage of mitosis, where the chromosomes line up at the centre of the cell
What is anaphase?
The third stage of mitosis, where cell fibres pull the chromosomes apart. The two arms of each chromosome go to opposite ends of the cell
What is telophase?
The fourth stage of mitosis, where membranes form around each of the sets of chromosomes. The nucleus has divided
What is cytokinesis?
When the cytoplasm and cell membrane divide to form two separate cells
How do plants and animals grow and develop?
Cell differentiation - cells becoming more specialised
Cell division - by mitosis
(In plants) Cell elongation - plant cells expanding
What is cancer?
When a change in one of the genes controlling cell division causes a cell to start dividing uncontrollably. This can result in a mass of abnormal cells called a tumour. If it invades and destroys surrounding tissue it is called cancer
What are stem cells?
Undifferentiated cells that can divide by mitosis to become new cells, which then differentiate
What is the difference between embryonic and adult stem cells?
Embryonic stem cells are found in early human embryos. They have the potential to divide and produce any type of cell.
Adult stem cells are found only in some places, like bone marrow. They can only produce some types of cells so they are not as versatile.
What are meristems?
A plant tissue found at the tips and roots of shoots (parts of a plant that are growing). They are the only cells in plants that divide by mitosis. They produce unspecialised cells that can divide and differentiate into any type of cell.
How are stem cells used in medicine?
Adult stem cells can cure some diseases, such as sickle cell anaemia with a bone marrow transplant. Embryonic stem cells are being experimented on to see if they could produce any type of cell
What are the potential risks with stem cells?
Tumour development - stem cells divide very quickly
Disease transmission - unnoticed viruses could be passed on in stem cells
Rejection - they could be recognised as foreign and trigger an immune response