Bbiology B2: Cells And Control Flashcards
(26 cards)
What does mitosis mean?
Cell division
Why do organisms like humans need new cells?
For growth and repair
What are the stages of the cell cycle? (in order)
- Interphase,
- mitosis: prophase, metaphase, anaphase
- cytokinesis
What happens during interphase?
The cell grows in size, DNA replicates and creates 2 identical copies of each chromosome.
What happens during prophase?
DNA condenses into visible chromosomes, the nuclear membrane breaks down and spindle fibres form
What happens during metaphase?
Chromosomes line up at the centre of the cell and spindle fibres form
What happens during anaphase?
The copies of each chromosome separate and are pulled to opposite poles of the cell by spindle fibres attach
What happens during telophase?
New nuclear membranes form around the separated chromosomes, and spindle fibres disappear.
What happens during cytokinesis?
The cytoplasm and cell membrane divide, creating two daughter cells which contain a complete set of chromosomes and is genetically identical to the original parent cell
What does differentiation mean?
The process by which a cell changes to become specialised
What does asexual reproduction mean?
When a single organism reproduces offspring on its own which are identical to the parent.
What are unspecialised cells called that he not been differentiated yet?
Stem cells
What are the two main types of stem cells in animals?
Embryonic stem cells and adult stem cells
What are the main features of stem cells in animals?
-They can divide by mitosis to form more cells
-They are able to differentiate into specialised cells
How do embryonic stem cells form?
When a sperm cell fertilises an egg cell to form a zygote, the zygote then divide many times by mitosis to form an embryo.
What can embryonic stem cells do
They can differentiate into ANY type of cell like nerve cells or skin cells
Where are adult stem cells found?
Bone marrow
What are the features of an adult stem cell?
-they can divide by mitosis
-can only differentiate into different types of BLOOD cells like platelets, red blood cells and white blood cells blood cells
What is the idea of adult stem cells?
They can replaced damaged cells to keep us alive but don’t form any new tissues.
Where are plant stem cells found?
Meristems, found at areas of plant which are continually growing
What do plant stem cells differentiate into?
Into ANY plant organ plants need to function like phloem and xylem and palisade cells.
Why are plant stem cells important?
The persist for the plants entire life, meaning they are always forming new tissue unlike embryonic stem cells which disappear later in life.
What is cancer?
When cells in the cell cycle start growing in an abnormal and uncontrolled way.
What are the 2 types of Tumors?
Beginne and malignant
