Growth And Development Flashcards
Nucleus
Controls what the cell does
Contains genetic information
Has a membrane extending from it with ribosomes attached
Cell membrane
Controls movement into and out of the cell
Cell wall
Made of cellulose
Strengthens and supports cell
Chloroplast
Contains chlorophyll- absorbs light energy to make glucose
Ribosomes
Where protein synthesis occurs
Located in the cytoplasm
What cells have no nucleus, mitochondria, chloroplasts or vacuole
Bacteria
Why does bacterial DNA float in circular strands
Bacteria have no true nucleus
What are two ways growth can be measured
Increase in height or mass
What is it called when cells specialise
In animal cells
The cells differentiate
How do plants grow
Cells elongate
Division occurs at the tip of plant roots and shoots (meristem)
Why dont animal cells have cell walls
Diffusion happens between them
Why do many plants never stop growing
They never lose the ability to differentiate
What are the tips of roots and tips of shoots known as
Meristems
What are advantages and disadvantages of using dry mass to calculate increase in growth
Most accurate method
Destructive, kills organism
In the human foetus what grows first
Head and brain, to coordinate the growth of the rest of the body
An embryo has differential growth
Why will it have a larger proportion of heart tissue
The circulation of blood is vital to growth and development of the embryo so is prioritised
Cell division is mainly restricted to tips of roots and shoots
In a plant what do the cells specialise into?
Xylem, phloem and a variety of others
What are stem cells
What do they have the ability to do
They are UNDIFFERENTIATED so can specialise into any type of cell, tissues and organs
Why are stem cells found in the embryo less limited than adult stem cells
Embryonic stem cells can specialise into any type of cell
Adult stem cells can only specialise into a limited variety of cells eg. Blood or bone cells
What are the potential uses of stem cells
Research- investigate how cell division goes wrong in diseases like cancer
Drug testing- test safety of new medicine
Transplants- replace damaged or diseased cell or grow organs for transplantation
Scientists need large numbers of embryos for stem cell use
How are they currently obtained
From IVF treatment
Remaining embryos are used
What are ethical conflicts about obtaining embryos for stem cell research
Embryos left over from IVF would be destroyed so stem cell research is a good use
Embryos have potential to become human beings so it is wrong to experiment with them
Vacuole
Filled with cell sap
Helps support celk
Where is DNA stored in plants
In plants however, DNA is stored in the nucleus
