cells & control Flashcards
What are the 2 types of cell production?
Mitosis (asexual)
Meiosis (sexual)
Mitosis is a ___ _____ that gives rise to…
cell division
two genetically identical diploid daughter cells
What 3 things is mitosis required for?
Growth, repair and asexual reproduction.
What are the stages of mitosis?
Interphase (I prefer muffins in the cafe)
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens in each stage?
I- dna copies itself exactly forming x shaped chromosomes
P- dna condenses, nuclear membrane breaks down
M- chromosomes line up on equator
A- chromosomes split down centre, pull each chromatid to either side of cell
T- new membrane forms around chromosomes
C- cytoplasm & membrane divides to produce 2 identical diploid daughter cells
What happens due to uncontrolled cell division?
Mutations in the dna of cells lead to uncontrolled cell growth & division, resulting in a tumour (mass of cells).
What are the two main types of tumour?
Benign
Malignant
What are benign tumours?
- Growths of abnormal cells contained in one area
- Do not invade other parts of the body meaning they’re not cancerous
What are malignant tumours?
- Cancerous since the cells invade neighbouring tissues & spread to different parts of the body through blood, forming secondary tumours.
- More likely to disrupt organ function as they invade healthy tissue (can lead to death).
What is cell differentiation?
Development of specialised features creating specialised cells.
What is cell elongation?
Hormones cause cells to grow longer in response to certain stimuli e.g. sunlight.
How do you monitor growth?
Growth charts - comparing growth to usual trends.
When monitoring growth in humans, what are the potential issues that can be evaluated?
Malnutrition, obesity, inconsistencies (large baby with small head etc), sudden changes in trend indicating new health problem.
As a ___________ organism develops its cells differentiate to form specialised cells.
Examples are…
Multicellular
Muscle cell, egg cell, brain cell, palisade cell.
Describe the cells in a multicellular organism.
Every cell contains the same genetic information but each cell has a different set of genes determining how the cell functions.
When the cell differentiates these active genes cause the development of _______ structures.
Sub cellular
Why do animal cells lose their ability to differentiate?
Most cells different an early state of its development so cell division is restricted to repair and replace.
Describe differentiation in plants.
Many plant cells retain the ability to fully differentiate throughout the plant’s life.
What is a stem cell?
Undifferentiated cell capable of dividing to produce many more cells of the same type.
What are the types of stem cell in animals?
Embryonic - form all different tissues & organs needed during development
Adult - more limited, can only differentiate to produce a few different cell types (replace & repair)
What are plant stem cells?
Meristem cells
What are the issues with using adult stem cells and embryonic stem cells?
They can only differentiate into a few cell types
There are clinical and ethical issues associated with embryonic stem cells - ‘the taking of innocent human life’ and they could trigger an immune response etc.
How are adult stem cells used in medicine?
- Cultured in lab and made to differentiate into specialised cells but fewer cell types than embryonic
- Can treat leukaemia
How are embryonic stem cells used in medicine?
- It’s possible to grow human embryos in the lab and extract embryonic stem cells from them
- They can be stimulated to differentiate into most types of specialised cell
- Can repair damaged organs
