Nat5 Biology Unit 2 Multicellular Organisms Key Area 1 Producing New Cells Flashcards
What is mitosis?
Division of the nucleus
A process of cell division that produces two genetically identical daughter cells
What does mitosis do?
Provides new cells for growth
Repairs damaged tissues
Replaces dead or damaged cells
Maintains the diploid chromosome complement
Stage one of mitosis
- Chromosomes condense: their DNA could up more tightly
Stage two of mitosis
- Each chromosome appears as two identical/sister chromatids held together by proteins at their centromere
Spindle fibres begin to form - structural proteins
Stage three of mitosis
The nuclear membrane is broken down
Replicated chromosomes line up on the equator of the cell.
Spindle fiber attach to each replicated chromosome (one fiber to each sister chromatid) at their centromere
Stage four of mitosis
Sister chromatids and separated by spindle fibers
Stage five of mitosis
The separated sister chromatids are now called chromosomes. They are moved towards the cell poles be spindle fibres
Stage six of mitosis
The chromosomes decondense: their DNA becomes less tightly coiled up. New nuclear membranes form around them and two genetically identical nuclei are formed
Stem cells in animals are…
Unspecialised cells which can divide to self-renew
Stem cells can become…
Different types of cells
Stem cells are involved in…
Growth and repair
Repair tissue damage (cuts,broken bones)
Stem cells can be…
Obtained from the embryo at a very early stage
Tissue stem cells cane be found in the body throughout life
What does specialization of cells lead to?
The formation of a variety of cells, tissues and organs doing different things (skin,blood)
What are groups of organs called?
Systems
What is the hierarchy?
Cells -> Tissues -> Organs -> Systems
What are spindle threads?
Protein threads that pull chromatids apart during mitosis
What is the equator?
The middle position of a cell where chromosome align and attach to spindle fibers in mitosis
What is a diploid cell?
A cell that contains a double set of chromosomes
What is the chromosome compliment?
The number of chromosomes found in a cell
What is a Chromatid?
The replicated copy of a chromosome
What is a haploid cell?
A cell that had one set of chromosomes (sex cells)
What are specialised cells?
Cells that do a specific job in the body
Through what process can stem cells become specialised?
Cell differentiation
What are the two main types of stem cells?
Embryonic stem cells
Tissue stem cells
What can embryonic stem cells become?
Any of the different types of cells
What can tissue stem cells become?
Only a few different types of cells
(Skin stem cells can only become skin cells, blood stem cells can only become blood cells, blood cells cannot be skin cells)
Through differentiation, what type of cell can a blood stem cells turn into?
Red blood cell
White blood cell
Cells that form platelets
Why do stem cells go through self-renewal?
So you don’t run out
Multicellular organisms have…… and are made up of …..
More than one cell type
Tissues and organs
The cells in organs are….
Specialised for their function and work together to form systems
