Cell questions

1. 1cm = 10mm 2. mm x 1000 = micrometres 3. micrometres x 1000 = nanometres

The ability to distinguish between two seperate points and see them as seperate entities.

The number of times larger an image is compared with the real size of the object.

1. Resolution of 200nm or 0.2 micrometres 2. Can view live specimens 3. Uses glass lenses to focus light 4. Images need to be stained

1. Resolution of around 3-10nm 2. Magnification of x100 000 3. A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected. 4. The inside of the microscope is a vaccum to ensure the electron beams travel in straight lines.

1. Resolution of upto 0.5 micrometres 2. Magnification of x500 000 3. Uses electrons fired at the object which is focused by electromagnets 4. Images are always black and white 5. Samples are stained with heavy metals e.g. uranium or lead 6. Electrons can't pass through denser parts of an object, so they appear dark

1. Uses florescent dyes and lasers 2. Moves a single spot of focused light across a specimen 3. The specimen has been treated with a florscent dye beforehand 4. When focused on the specimen it causes florscence 5. The emitted light is filtered through a pinhole aperture

The absorption and re-radiation of light

IAM

1. Cheap to purchase and operate 2. Low resolution and magnification 3. Uses light 4. Specimens can be either dead or alive 5. Focused by lenses 6. Natural colour can be observed 7. Portable 8. Preparation of materials are quick 9. Image formed on retina

1. Expensive to purchase and operate 2. High resolution and magnification 3. Focused by magnets 4. Specimens are dead 5. All images are black and white 6. Operated in special rooms 7. Preparation of materials is lengthy 8. Image formed on computer

Visible structural details caused by processing a specimen and is not one of the features of them.

Made up of multi-cellular organisms. Complicated internal structures containing a membrane-bound nucleus and cytoplasm

Single-celled organisms with a single internal area called the cytoplasm - composed of cystol which contains water and salts

Responsible for containing all of the genetic information of the cell in the form of DNA and directs protein synthesis.

Protects the DNA from damage in the cytoplasm and contains nuclear pores

Allows molecules to move into and out of the nucleus

Responsible for producing ribosomes. Composed of proteins and RNA, which are used to produce rRNA which combines with proteins to form ribosomes.

The powerhouse of the cell and the site of ATP synthesis. Also the site of the final stages of cellular respiration. The number of mitochondria present in a cell is a direct reflection of how much energy it uses.

Membrane sacs that have storage and transport roles. Consist of a single membrane with fluid enclosed.

Specialised forms of vesicles that contain hydrolytic enzymes which are responsible for breaking down the waste materials in cells. Plays an important role in the immune system

A network of fibres necessary for the shape and stability of a cell. Controls cell movement and the movement of organelles within cells.

1. Microfilaments 2. Microtubules 3. Intermediate fibres

Formed from actin and is responsible for cell movement and cell contraction during cytokenesis

Made of globular proteins and determines the strucutre of a cell. They also act as tracks for the movement of organelles, including vesicels around the cells.

Microtubules

Provides mechanical strength and helps maintain integrity.

Component of the cytoskeleton and is composed of microtubules. Two centrioles form the centrisome.

Involved in the assembly and organisation of the spindle fibres during cell division.

Present on the surface of many cells and have an important role in sensory organs e.g. the nose

Beats in a rhythmic manner, creating a current and causing fluids to move.

A network of fibres enclosing flattened sacs called cisternae. It is connected to the outer membrane of the nucleus.

Responsible for lipid and carbohydrate synthesis and storage.

Contains ribosomes bound to its surface and is responsible for the synthesis and transport of proteins.

Either free floating or attached to the rough ER and is the site of protein synthesis.

Formed of cisternae and modifies proteins and packages them into secretory vesicles or lysosomes if they are to stay in the cell.

1. DNA containing the instructions for proteins leaves the nucleus via the nuclear pores as mRNA. 2. Proteins produced on the ribosomes bind to the rough ER. 3. It passes into the cisternae of the rough ER and packaged into transport vesicles. 4. Moves towards the golgi apparatus via the transport function of the cytoskeleton (microtubules) 5. The vesicles fuse with the golgi apparatus and the proteins enter. They are structurally modified before leaving the gologi in packaged vesicles. 6. Secretory vesicles carry proteins to the cell surface membrane to fuse with it and release its contents by excocytosis. Some proteins are packagd into lysosomes which contains enzymes for use in the cell.

Plant cells are rigid and have a cell wall surrounding the cell-surface membrane. The cell wall is made out of cellulose.

1. They are freely permeable so substances can diffuse in and out. 2. Gives the plant its shape 3. The contents of the cell presses against the cell wall making it rigid (turgor pressure) 4. Acts as a defence mechanism as a barrier to pathogens

Membrane lined sacs in the cytoplasm containing cell sap and is important in the maintenance of turgor pressure.

The membrane of a vacuole. It is selectively permeable.

Responsible for photosynthesis

They have a double-membrane structure, similar to mitochondria.

The fluid enclosed in the chloroplast

Membranes which form flattened sacs

Several thylakoids stacked together. They are joined by membranes called lamellae.

As starch grains present in the chloroplast.

Cells adapted to living in extremes of salinity, pH and temperature. e.g. some forms of bacteria living in deep sea vents.

Thinner, doesn't have the 9+2 arrangement and the energy to move it is supplied from chemisosmosis rather than ATP.

Circular

Linear

Proteins fold and condense DNA.

Associated with proteins called histones

Peptidoglycan

1. Fungi = Chitin 2. Plants = Cellulose

70s

80s

Binary fission

Assexual or sexual reproduction

Unicellular

Unicellular or multicellular