Cell stucture 2.1 Flashcards by Isabel Mur

What is magnification?

The number of times bigger the image is compared to the actucal size of the object

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What is resolution?

The ability to see two objects that are close together as two separate objects, or the ability to see detail

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What is a photomicrograph?

Photograph of an image seen using an optical microscope (light microscope)

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What is the maximum resolution and magnification of a light microscope?

magnification - X1500
resolution - 200nm

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Positives of a light microscope

+ cheap
+ portable
+ easy to use
+ can view whole living specimens

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Negatives of a light microscope

low magnification
low resolution
specimens have to be thin to let light through

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What are the positives of electron mircoscopes?

+ higher resolution
+ SEM gives 3D images giving detailed views of cell surfaces
+ produce detailed images of structures inside cells

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What are the negatives of electron microscopes?

expensive
need trained staff
samples need to be dead due to the vacuum

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What are the characteristics of a laser scanning confocal microscope?

can observe whole living specimens
high resolution
high contrast
focuses on structures at different depths within a specimen

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What are the characteristics of a transmission electron microscope (TEM)?

uses electrons
samples have to be dead in a vacuum
2D image

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What is the maximum resolution and magnification of a TEM

magnification - X500,000
resolution - 0.02nm

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What are the characteristics of a scanning electron microscope (SEM)?

3D image
gives detailed surface view of the outside of cells
electrons bounce off specimens

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What is the maximum resolution and magnification of a SEM?

magnification - X100,000
resolution - 0.5-0.1nm

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What is the calculation for magnification?

Magnification = Image / Actual object

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What is the distance between each small division on the stage mircometer?

10 micrometers

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What equipment do you need to calibrate a microscope?

stage micrometer
eyepiece graticule

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How do you calibrate a microscope?

You need to work out how many micrometers each eyepeice unit represents

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What is ultrastructure?

Anything inside the cell

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What is a eukaryote?

An organism that consists of one or more cells contain DNA in a membrane bound nucleus and membrane bound organelles separate from the cytoplasm

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Which of the kingdoms are eukaryotic?

Animal, plant, fungi and protoctist

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What are the functions and characteristics of the nucleus?

stores organisms genome
transmits genetic information
provides instructions for genetic info
double membrane bound

What are the functions and characteristics of the nuclear envelope?

separates contents of the nucleus from the rest of the cell
double membrane
contains pores
contols what substances enter and leave the cell

What are the functions and characteristics of the nucleolus?

not membrane bound
contained RNA
where ribosomes are made

What are the functions and characteristics of the rough endoplasmic reticulum (RER)?

system of membranes continuous with the nuclear membrance, coated in ribisomes
processes proteins

What are the functions and characteristics of the smooth endoplasmic reticulum (SER)?

- system of membranes continuous with the nuclear membrance - synthesises and processes lipids

What are the functions and characteristics of the golgli apparatus?

- stack of membrane bound flattened sacks - packages and modifies proteins

What are the functions and characteristics of the mitochondria?

- double membrane where the inside membrane is highly folded - site of ATP production and aerobic respiration - has its own DNA and ribosomes

What are the functions and characteristics of the chloroplast?

- site of photosynthesis - contains stacks of thylakoids called granum - found in a fluid called stroma - has its own DNA and ribosomes

What are the functions and characteristics of the vacuole?

- surrounded by a membrane called tonoplast and is filled with fluid - filled with water and solutes to push against cell walls to make the cell turgid

What are the functions and characteristics of the lysosomes?

- small bags formed from the golgi - contain digestive enzymes - digest old organelles or foreign bodies

What are the functions and characteristics of the ribosomes?

- made of RNA - site of proteinsynthesis

What are the functions and characteristics of the cell wall?

- rigid structure that surrounds cells - acts as a defense mechanism - cellulose in plant cells - chitin in fungi - peptidoglycan in bacteria

What are the functions and characteristics of the plasma membrane?

- membrane found on the surface of cells - regulates movement of substances in and out of the cell

What are the functions and characteristics of the cytoskeleton?

- network of protein structures - provides mechanical strength - allow tracks for intracellular transportation - aid in mitosis - anchor organelles

What are the functions and characteristics of the microtubules?

- tublin proteins forming a hollow tube - provides tracks for motor proteins - forms spindles to aid in mitosis

What are the functions and characteristics of the flagella?

- long hair like structure that extends from cell surface - 9 pairs of microtubles arranged in a circle with a pair in the centre - contains motor proteins that move along microtubules generating force, for cellular locomotion

What are the functions and characteristics of the cilia?

- many microtubules extending from cell surface - move to waft mucus - 9 pairs of microtubles arranged in a circle with a pair in the centre

What are the functions and characteristics of the centrosomes?

- stuctures that act as microtubule organising centre - duplicate before cell division

What are the functions and characteristics of the centrioles?

- form hollow cylinders containing a ring of microtubules arranged at right angles to eachother - found only in animal cells - involved with separation of chromosomes during mitosis

What does cis and trans face mean?

Cis face means facing the nucleus and trans face means facing away from the nucleus

What is the process for the formation of a protein?

- proteins produced in ribosome - proteins on RER surface are folded and processed in the RER - they are transported to the golgi apparatus in vesicles - modified and packeged in the golgi - put into vesicles and transported to the plasma membrane - fuse with the membrane to perform exocytosis

What is a prokaryote?

A single celled organism without a nucleus that does not contain membrane bound organanelles

What are three examples of single celled eukaryotes?

Yeast, amoeba and paramecium

What is the endosymbiotic theory?

The theory that mitochondria and chlopoplasts in eukaryotic cells were once separate prokaryotic microbes

What ultrastructure do both eukaryotes and prokaryotes contain?

- cytoplasm - ribosomes - plasma membrane - DNA and RNA

What are the ultrastructure that only prokaryotes contain?

- slime capsule - flagellum - plasmid - pili - circular DNA

How are prokaryotes different to eukaryotes?

- much smaller - no nucleus - no membrane bound organelles (mitochondria) - wall made of peptidoglycan - smaller ribosomes - some contain flagella and pili

What are pili and what is their function?

- hair like structures - allow bacteria to adhere to eachother/ host cell

What kind of stain stains nucleus?

Methylene blue

What does staining do?

Provides contrast so specimens are easier to see and observe

What is sectioning?

Embedding a species in wax to make it easier to cut without distorting