Biology module 1.1 Flashcards by Carla long

Why does magnification only have its limits?

Because soon objects only become bigger and vaguer, if an object is less than the distance of half the wavelength of light apart it cannot be distinguished as separate

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What microscope can organelles be seen with? Why?

Organelles can only be seen clearly with an electron microscope this is because electron microscopes have a greater magnifying power

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What are prokaryotic and eukaryotic cells?

Bacteria and cyanobacteria

All other cells such as plant, fungi and animal

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What four items make up the nucleus?

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How are eukaryotic cell characterised?

They have membrane-bound organelles

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What is endoplasmic reticulum?

A system of flattened cavities lined by a thin membrane

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What are the two types of endoplasmic reticulum?

Smooth and rough

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What happens in SER

It is where lipids and steroids are made

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Where would you find a lot Of SER?

In the liver cells as this is where lipids are metabolised

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Why does the RER look rough and what does it do?

It is studded with ribosomes

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What does the Golgi apparatus do?

-Once the proteins in the RER pinched off at the end of the cavity
-surrounded by thin layer of membrane (vesicle)
-Once moved through the cytosol it will fuse with the membraneGolgi apparatus
-They are then modified for export from the cell (eg carbohydrate added on)
-vesicle fuses with the membrane and is released
-

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What is a lysosome?

Vesicle containing digestive enzymes

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What is produced during respiration?

ATP

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What are microtubules?

Hollow structures with walls of tubulin protein

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What do centrioles do and where are they found?

Involved in the formation of spindle fibres used in mitosis?

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What is the membrane made out of?

Is made up with a sea of phospholipids with protein molecules floating in between the phospholipids

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What do glycoproteins do?

They help in recognising cells and interaction with other cells
Hormones and foreign molecules

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How are phospholipids arranged?

The phosphate heads are polar molecules and are water-soluble
lipid tails are non-polar so not water-soluble

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What is attached to the outer surface of the membrane?

Glycoproteins

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Name 4 functions of the membrane?

Keep the cell contents together
Allows communication with other cells
Allows mobility in some organisms
selectively permeable barrier

What is facilitated diffusion?

Diffusion that uses Either a channel protein or a carrier protein

What is pinosytosis?

When minute vesicles are formed for liquid material

What is a tissue?

A group of cells that are collectively together and perform one or more particular functions

What does palisade mesophyll do?

Harnesses light energy required to photosynthesise

Name some examples of tissues?

Squamous and ciliated epithelia | Xylem and Phloem

How does a light microscope work?

- The beam of light comes from the bulb under the stage - passes through a condenser lens - going through the specimen

What are the four objective lens usually present in a microscope?

X4 X10 X40 X100

What is the magnification and resolution of a light microscope?

X1500 Magnification | 200nm Resolution

What specimens can be seen with a light microscope?

Live organisms such as daphnia and euglena Smears of blood and cheek cells Smaller cuttings of larger plants and animals

How does a transmission electron microscope work and what is its magnification?

-Electronbeam is directed onto a sample -electron-beam passes through -the denser parts of the sample are harder for the electrons to get through So contrast X500000

What is the cytoskeleton

Network Of protein of Fibres found within sales that gives structure and shape to the cell and also moves organelles around inside cells

What provides movements in cells

Microtubules

Where do microtubules get energy from

ATP

What is cellulose

A carbohydrate polymer made up of glucose subunits

Suggest 2 ways that cell division In plants differs from cell division in animals?

Cell division only occurs in the meristems | In plants a plate forms between new cells

What colour does iodine solution stain starch and other structures?

Black | Yellow

What are SEM's used for?

Viewing the surfaces of samples, they produce an image of a 3 dimensional shape

What do TEM's show you?

Internal structure of thin section

What is the wavelength and resolution of a light microscope?

400nm | 200nm

What is the wavelength and magnification of a EM

1. 0nm | 0. 5nm

What is maximum magnification in LM TEM SEM

x1500 x250000 x100000

What are example of cell signals?

Cytokines

What are the two types if phloem cells?

Sieve tube elements | Companion cells

How are companion cells and sieve tube elements linked?

Through many plasmodesmata

Why do sieve tubes have a thin layer of cytoplasm?

Reduce resistance to the flow of sap

What is cohesion?

Attraction of water molecules for one another

What is adhesion

Attraction of water molecules for the xylem

Where is the casparian strip found?

In specialised cell walls in the endodermis

How does water move up the stem?

Root pressure Transportation pull Capillary action