2. Organisation of the organism Flashcards
2.1 Cell structure 2.2 Size of specimens
Cells
The smallest basic units of all living organisms.
Cell membrane
The boundary of a cell, which regulates the movement of substances into and out of the cell.
Cytoplasm
A jelly-like substance that is the site for most chemical reactions in a cell.
DNA
A large molecule made from bases, and which carries genetic information in the form of genes.
Nucleus
The nucleus is an organelle found in animal and plant cells. It contains genetic information (DNA) and controls all the activities of the cell.
Ribosomes
Sub-cellular structures in which protein synthesis takes place.
Mitochondria
(singular: mitochondrion) Sub-cellular structures that release energy for the cell by aerobic respiration.
Chloroplasts
Sub-cellular structures found in some plant cells; the site of photosynthesis.
Which kingdom’s cells do not include mitochondria?
Prokaryotes
Chlorophyll
Green pigment found in plants, which absorbs energy from sunlight for photosynthesis.
Vacuoles
Relatively large, permanent structures in plant cells, filled with cell sap.
Cell wall
The outer layer of a plant cell, made of a network of cellulose fibres.
Circular DNA
Chromosomal DNA found in bacteria.
Plasmids
A short loop of DNA found in bacteria that is not part of the bacteria’s chromosome.
Root hair cells
Type of cell in plant roots that has a large surface area for the absorption of water and mineral ions from the soil.
Palisade mesophyll cell
Specialised cell in leaves packed with many chloroplasts for photosynthesis.
Ciliated epithelial cell
Type of specialised cell with cilia (fine hairs) that sweep mucus out of the trachea.
Neurone
A neurone is a specialised cell that transmits electrical nerve impulses.
Red blood cell
Type of animal cell that contains haemoglobin, and which transports oxygen around the body.
Egg cell
The female gamete. Also called an ovum (plural: ova).
Sperm cell
The male gamete in humans and other animals.
Cell cycle
Series of stages that takes place in a growing and dividing cell
Mitosis
A form of nuclear division that gives rise to genetically identical cells.
Flagellum
Long, thin parts that protrude from unicellular organisms to assist movement.
Rough endoplasmic reticulum
Involved in the manufacture and transport of proteins (has ribosomes)
Smooth endoplasmic reticulum
Involved in the synthesis and storage of liquids (has no ribosomes)
Golgi apparatus
Complex of vesicles + folded membranes involved in secretion and intercellular transport.
Transport vesicle
Transports “cargo” (usuall proteins) from endoplasmic reticulum to golgi
Secretory vesicle
A vesicle that transports “cargo” to the cell membrane where it fuses and “cargo” leaves.
Pili
Protruding parts of prokaryotic (bacteria) cells. Provide link to external environment (attatch to, host etc.)
Glycocalyx (capsule)
Stops bacteria being identified by white blood cells.
Septum
Internal cross walls called “septa” between hypae cells in mycellium. (fungi)
Resolution
The degree to which it is possible to distinguish between two objects that are very close together.
Magnification (def)
The degree to which the size of an image is larger than the object itself.
Magnification (formula)
Size of image / Actual size of image
How many cm in a metre?
100cm
How many mm in a cm
10mm
How many micrometres in a mm
1000μm
Tissue
A group of cells with similar structures, working together to perform a shared function.
What are the four basic tissues in the human body?
Muscular tissue, Nervous tissue, Connective tissue, Epithelial tissue.
Muscular tissue
Cells can contract and relax to allow movement.
Nervous tissue
Different neurones allow messages to be carried to and from the brain.
Connective tissue
Examples inclue blood, bone, fat and cartilage.
Epithelial tissue
Lines organs. Cells are regular geometric shapes and have obvious nuclei. (usually have protruding shapes, eg. ciliated epithelial cell).
Organ
A structure made up of a group of tissues working together to perform specific functions (the tissues may not have the same specific functions).
Organ system
A group of organs with related functions, working together to perorm body functions (eg. respiratory system, digestive system, skin etc.)
Magnification (formula)
Magnification = Size of image / Size of object
1 µm = ? mm
1 µm = 0.001 mm
1 micrometre
1 µm = 0.001 mm
Converting between micrometres and millimetres
µm → mm divide by 1000
mm → µm multiply by 1000
Levels of organisation
Cell → Tissue → Organ → Organ System → Organism
Tissue
A group of cells with similar structures, working together to perform a shared function.
Organ
A structure made up of a group of tissues working together to perform specific functions.
Organ System
A group of organs with related functions, working together to perform body functions.
Circulatory System (example of levels of organisms)
- Many smooth muscle cells group together to form tissue.
- Layers of smooth muscle tissue make up organs.
- Arteries are organs containing layers of smooth muscle tissue that transport blood out of the heart (one of the other organs in the circulatory system)
- Arteries do this job to help the circulatory system perform its function as an organ system.
- This and other organ systems, each with different functions, work in a coordinated way to keep an organism’s body working.
Examples of Organ systems
- Plant shoot
- Plant root
- Digestive system
- Circulatory system
- Immune system
- Respiratory system
- Excretory system
- Nervous system
- Reproductive system
Bacteria cell - Parts we need to know
Cell wall, cell membrane, cytoplasm, ribosomes, circular DNA, plasmids.
Don’t need to know
Pilli, glycocalyx, (sometimes flagellum)
