Cells & Specialisation Flashcards
Cells
Tiny, microscopic units.
All living things are made up of them
Cells
Animal Cell Structures
Cell Membrane Chromosomes Cytoplasm Mitochondria Nuclear Membrane Nucleus
Plant Cell Structures
Cell Membrane Cellulose Cell Wall Chloroplasts Chromosomes Cytoplasm Large Permanent Vacuole Mitochondria Nuclear Membrane Nucleus
Nucleus
3 marks
Control centre of the cell - containing genetic material
- arranged in the chromosomes of most cells.
Chromosomes
Threadlike structure.
Found in Nucleus.
Made of DNA - contains genetic info of cell.
Usually occur in functional pairs in the nucleus of cells (except gametes and bacteria).
Cytoplasm
The living substance inside a cell (not including the nucleus).
Chemical reactions take place here.
Mitochondria
Power house of the cell.
Site of Cell Respiration.
Abundant in cells that need energy
(E.g Muscle Cells)
They are Structures in the cytoplasm of all cells where aerobic respiration takes place.
Singular; mitochondrion.
Cell Membrane
Selectively permeable (semi-permeable) barrier.
Surrounds cell.
Allows some substances to enter/leave the cell.
Prevents others.
Nuclear Membrane
Surrounds Nucleus.
Cellulose Cell Wall
Rigid structure outside the Cell Membrane.
Against Cell Wall.
Provides support.
Large Permanent Vacuole
Found within the Cytoplasm; contains Cell Sap.
When full pushes Cell Membrane against Cell Wall.
Provides support.
Chloroplasts
Found in Leaf Cells.
Part of a cell that carries out photosynthesis.
Contains Chlorophyll
Chlorophyll
Green pigment that traps (sun)light in order to convert:
Carbon Dioxide + Water
into —>
Glucose (Chemical Energy) + Oxygen
in a process known as Photosynthesis
Bacteria
Single-celled organisms
Lack a nucleus;
Prokaryotes
Bacteria Structure
Cell Membrane
Cytoplasm
Non-cellulose Cell Wall
Plasmids
Do not contain a nucleus (prokaryotes)
Where are plasmids found in Bacteria?
Floating in cytoplasm.
Plasmids
Extrachromosomal DNA molecule (rings of DNA)
Found (floating) in Cytoplasm.
Stem Cells
Unspecialised cells found in plants and animals.
Have the ability to divide; to form cells of the same type.
Can differentiate into a variety of specialised cells.
Can be harvested from embryonic umbilical cord/adult bone marrow.
Embryonic Stem Cells
Can form a full range of cell types but many at an early stage will have changed permanently into specialised cells;
which can’t specialise into anything else.
Stem Cells from Bone Marrow
Only form a limited range of cell types (blood cells)
Stem Cells in Plants
Found in apical meristems at the end of shoots and roots.
Cells produced here = able to divide until they’re in their final position in root/stem/leaf.
Specialisation can still be reversed under certain conditions - meaning scientists are able to produce large no.’s of genetically identical plants in a short period of time through cloning.
Differentiate
When a cell becomes different in order to carry out a (particular) function.
Specialised Cells
Cells adapted to carry out a particular function.
Harvested
Process of collecting stem cells.
Umbilical Cord
Cord that connects the foetus to the placenta - contains blood vessels
Blood Marrow
Soft tissue found inside bones;
Produces new blood cells.
Meristems
Tissue in growing parts of plants;
Contains Unspecialised Stem Cells.
Cloning
Process that produces Genetically Identical Organisms.
Types of Organisms
Single-celled
Multi-celled
Single-celled Organisms
Where all life processes are carried out by 1 cell.
Multi-celled Organisms
Where cells differentiate and become specialised to carry out a particular function.
Example of Multi-celled Organism
Red Blood Cells Carry Oxygen.
Tissue
Cells with the same structure and function.
Tissue Example
Muscle Tissue
Organ
7 types of tissue that carry out a particular function.
Organ tissue Example
Heart Organ contains Muscle and Nerve tissue.
Organ System
Organs that work together to carry out a particular function.
Example of Organ System
Circulatory System
Circulatory System is made up of;
Heart
Blood Vessels
Blood
Circulatory System (Transport System) Functions
Delivers nutrients and other essential materials to cells.
Whilst removing waste products.
Provide all cells with substances like oxygen.
Benefits of using Stem Cells in Medicine
Treating Leukaemia
Bone Marrow Transplant
How are Stem Cells used to treat Leukaemia?
Chemo/radiotherapy destroy WBC in the patients body.
Stopping Bone Marrow from producing new blood cells.
How are Stem Cells used in a Bone Marrow Transplant?
Transplant containing stem cells from a matching donor - allows healthy blood cells to be made in the patient.
WBC
White Blood Cells
RBC
Red Blood Cells
Risks of using Stem Cells in Medicine
Infection from Environment or Donor.
Division of Stem Cells - leading to a tumour or unwanted cell types.
Transfer of Viruses/Diseases.
Risks of using Stem Cells in Medicine:
Infection from Environment or Donor
As Chemo/Radiotherapy leave the patient with No Immune System.
Risks of using Stem Cells in Medicine:
Division of Stem Cells - leading to a tumour or unwanted cell types
(Stem) Cell division in an uncontrolled manner may lead to the formation of Tumours or the development of Unwanted Cell Types.
Risks of using Stem Cells in Medicine:
Transfer of Viruses/Diseases
From other animals.
Ethical Issues with the use of Stem Cells in Medicine
Use of Embryonic Stem Cells.
And Governments Controlling Research in this area.
Ethical
Relating to moral principles
Or the branch of knowledge dealing with these.
Peer Review
New research carried out in any field of science is validated/ rejected
By groups of other scientists/experts in the same field
To ensure any conclusion drawn from scientific investigations are correct.
Chemotherapy
The use of chemicals to treat cancer.
Chemicals used are highly toxic to cells that divide rapidly.
Where do Chromosomes usually occur?
Usually occur in functional pairs in the nucleus of cells (except gametes and bacteria).
Stem Cell: Simplified
A type of stem cell found in the embryo, capable of dividing into almost any cell type.
Immune System
Body’s defence system against entry of any foreign body, including pathogens and agents such as pollen grains.
Role; to prevent disease.
Leukaemia
Type of cancer that affects the WBC.
Radiotherapy
Treatment of cancer with X-rays or gamma rays.
