Chapter 3 - Cell Structure Flashcards by KJ Hall

What structures are included in the eukaryotic cells for animals?

nucleus
mitochondria
rough endoplasmic reticulum (RER)
smooth endoplasmic reticulum (SER)
golgi apparatus
lysomes
ribosomes
cell surface membrane

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Describe the nucleus and its function

nuclear envelope surrounding chromatin + nucleoplasm

* FUNCTION: stores genetic info to make protein and makes ribosome

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Describe the mitochondria and its function

double membrane
inner is highly folded (cristae)
FUNCTION: synthesis energy rich ATP molecules during aerobic respiration

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Describe the rough endoplasmic reticulum and its function

network of interjoined sheets studded with ribosomes

* FUNCTION: ribosomes synthesis proteins and channels transport these proteins

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Describe the smooth endoplasmic reticulum and its function

Soft surface and tubular appearance

* FUNCTION: synthesis, store and transports lipids

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Describe the golgi apparatus and its function

from RER then excretes to cell-membrane

* FUNCTION: Modifies proteins or lipids and packages them into vesicles for export

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Describing lysosome and its function

contains hydroletic enzymes

* FUNCTION: Fuses worn out organelles/enzymes digest organelles

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Describe ribosomes and its function

Contains rRNA and protein
Occurs in cytoplasm or RER
FUNCTION: Makes proteins

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Describe cell-surface membrane and its function

fluid Mosaic model

* FUNCTION:Controls the entry and exit

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Calculate magnification

Image/actual (IAM)

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What structures are included in eukaryotic cells for plants?

cell wall
chloroplast
Vacule

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Describe a cell wall and its function

polysaccharides (cellulose)
thin layer called middle lamellar makes boundary between adjacent cells and cernents adjacent cells
FUNCTION: mechanical strength to prevent bursting of cell allowing only water to pass

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Describe chloroplasts and its function

chloroplast envelope with double plasma membrane and highly selective
FUNCTION: harvesting sun light - carries out photosynthesis

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Describe a vacule and its function

•FUNCTION: stores H2O

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What is a transmission electron microscope?

Passes electrons through specimen giving 2-D images

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What is the scanning electron microscope?

Passes electron over the surface of specimens given 3-D imaging (low resolution)

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What is an advantage of electron microscope?

High resolving power as electrons have a shorter wavelength than light microscopes

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What are disadvantages of a lecture microscopes?

Systems must have a vacuum - Cannot observe living specimen
complex staining – yet picture not coloured
specimen must be thin
may contain artefact - From the way specimen prepared changing appearance
expensive

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Describe the process of ultracentrifugation

•tissue homogenised in a blender in a solution which is: cold (inactivate enzyme)/isotonic (stops gaining/losing water)/buffered(keep the pH the same)
•tube span at high speed (1000 revs min^-1)
•pellet 1 - nucleus
•supernate removed (all except nuclei)
•run at higher speed
•pellet 2 - chloroplast/mitochondria
Repeat

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What’s the fluid left after the cells are broken up by homogeniser releasing organelles from cell?

Homogenate

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The two types of electron microscopes?

Transmission electron microscope

* Scanning electron microscope

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When using a light microscope we can measure the size of objects using…………….

An eyepiece graticule

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To calibrate an eyepiece graticule you need to use a special microscope slide called a ……………..

Stage micrometer

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Describe cell specialisation

It’s cell adapted to have a particular function and perform it to make it more efficient

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Describe a tissue

A collection of similar cells for a specific function

Describe an organ

A collection of tissues to perform a variety of functions

Put an order in organ, cells, tissues and organs system.

Cells, tissues, organs and organ system

Given two examples of a tissue

* Epithelial tissue - found in animals and consists of sheets of cells * Xylem – found in plants transporting water and minerals ions through the plant

Give two examples of an organ

* muscle – to churn up the stomach contents | * Palisade mesophyll - made up of leaves palisade cells that carry out photosynthesis

Give three examples of an organ system

* The digestive system – digests and processes food * Respiratory system - useful breathing and gas exchange * The circulatory system - pumps and circulates blood

Compare a prokaryotic and eukaryotic cell:

Prokaryotic cell – no nucleus/DNA is not associated with proteins/some DNA may be found in circular strand (plasmid)/no membrane/no chloroplast/ribosomes are smaller/cell wall made out of murine Eukaryotic cell – distinct nucleus/do you need Societie proteins/no plasmid/DNA is linear/mitochondria are presents/chloroplast are present/ribosomes are larger

Name the cell structures in a bacterial cell

* cell wall * capsule * cell-surface membrane * circular DNA * plasmid

Define the role of the cell wall in a bacteria

Physical barrier that exclude certain substance and protects against mechanical damages

Define the role of a capsule in a bacteria

Protects bacteria from other cells and helps groups of bacteria to stick together

Define the role of cell-surface membrane in the bacteria

Controls what enters and exits chemically

Define the role of circular DNA in bacteria

Genetic information for replication of bacteria cells

Define the role of plasmid in a bacteria cell

Possesses genes that may aid aid survival of bacteria in at this condition

What structures are in the virus?

* attachment protein * capsid * lipid envelope * matrix * reverse transcription * genetic material

What is mitosis?

Produces two daughter cells that have the same number of chromosomes as the parent cell and each other

What is meiosis?

Produces for daughter cells, each with half the number of chromosomes of the parents cell

What are the five stages of mitosis?

* interphase * prophase * metaphase * anaphase * telophase

What can you use to remember the mitosis stages?

IPMAT

Describe the interphase stage

* Growth * DNA REPLICATION ( 1 chromosome = 2 chromatids) * Replicates ATP and organelles * Chromosomes invisible

Describe the prophase stage

* Chromesomes become visible (Short/condense) | * Nuclear envelope disappears

Describe the metaphase stage

• chromosomes attached to spindle fibres at the centromere

Describe the anaphase stage

* Spindle fibres contract * chromatids separate to opposite poles * Energy from mitochondria

Describe the telophase stage

* Chromatids reached piles * Nuclear envelope forms two clusters * Cytoplasm divides

What are the three stages of the cell cycle?

* nuclear division * cytokines * interphase

What is an object?

The material placed under the microscope

What is an image?

The appearance of the material viewed under the microscope

What is resolution?

How well a microscope can distinguish between two points that are close together

Maximum resolution of a light microscope

0.2 micrometres

Maximum magnification of a light microscope

1500 x

Maximum resolution of electron microscopes

0.0002 micrometres

Maximum magnifiation of electron microscopes

1,500,000 x

What are artefacts?

Things that you can see on the microscope but aren't part of your specimen

How many micrometres are in a millimetre?

1,000

How many nanometres are in a micrometre?

1,000

How to calibrate a microscope?

1) Divide total length of stage micrometre by how many intervals to find one micrometre unit 2) Find a point where the two lines are equal 3) Work out how many micrometre units equal how many eyepiece units 4) Convert the stage micrometre units to micrometres 5) Divide stage micrometre units by eyepiece units to find the value of one eyepiece unit 6) This can be used in calculations

What is cell fractionation?

The process where cells are broken up and different organelles they contain are separated out

What happens during ultracentrifugation?

The filtrate is poured into a test tube, placed in the centrifuge and spun slowly The heaviest organelles sink to the bottom, forming the pellet, whilst the rest of the organelles stay suspended in a fluid called the supernatant The supernatant is drained off, poured into another test tube and spun at a higher speed The next heaviest organelles form the pellet and are removed The process repeats until the desired organelle forms the pellet, which can then be studied

What are grana?

Stacks of thylakoid membranes inside chloroplasts

What is the stroma?

A matrix where the sugars are synthesised during photosynthesis