C1 (Cytology And Microspy)

Question 1

What are organelles

Answer 1

Parts of cells. Each with specific function

Question 2

What’s the cell ultrastructure

Answer 2

The organelles and internal structure within organelles

Question 3

What are the two main types of organisms

Answer 3

Eukaryotic organisms (cells) and prokaryotic organisms (cells).

Question 4

What organelles do plant cells have that animal cells don’t

Answer 4

Permanent vacuole
Cell wall
Chloroplast
Plasmodesmata

Question 5

Plasma membrane

Answer 5

Membrane found on surface of animal cells and just inside cell wall plant cells and prokaryotic cells

Mainly made of lipids and protein

Question 6

Plasma membrane function

Answer 6

Regulates movement substances into and out of the cell

Has receptor molecules, which allow it to respond to chemicals (like hormones)

Question 7

Cell wall

Answer 7

A rigid structure that surrounds plant cells

Made mainly of the carbohydrate cellulose

Question 8

Cell wall function

Answer 8

Supports plant cells

Question 9

Nucleus

Answer 9

Large organelle surrounded by a nuclear envelope (double membrane) which contains many pores

The nucleus contains chromatin (made of DNA and proteins) and often a structure called nucleolus

Question 10

Nucleus function

Answer 10

It controls cell’s activity (by controlling the transcription of DNA).

DNA contains instructions to make proteins.

The pores allow substances (RNA) to move between nucleus and cytoplasm

Nucleolus makes ribosomes

Question 11

Lysosomes

Answer 11

A round organelle surrounded by a membrane, with no clear internal structure

Question 12

Lysosomes function

Answer 12

Contain digestive enzymes, kept separate from cytoplasm by surrounding membrane

Used to digest invading cells.or break down worn out components of cells

Question 13

Ribosomes

Answer 13

Very small organelle
Either free floats in cytoplasm or is attached to rough endoplasmic reticulum

Made out of proteins and RNA
Not surrounded by a membrane

Question 14

Ribosomes function

Answer 14

Site where protein synthesis takes place (where proteins are made)

Question 15

Rough endoplasmic reticulum

Answer 15

A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes

Question 16

Rough endoplasmic reticulum function

Answer 16

Folds and processes proteins that have been made at the ribosomes

Question 17

Smooth endoplasmic reticulum

Answer 17

Similar to rough endoplasmic reticulum, but with no ribosomes

Question 18

Smooth endoplasmic reticulum function

Answer 18

Synthesises and processes lipids

Question 19

Vesicle

Answer 19

A small fluid-filled sac in cytoplasm by a membrane

Question 20

Vesicle function

Answer 20

Transports substances in and out of the cell (via plasma membrane) and between organelles.

Some are found in golgi apparatus or the endoplasmic reticulum, while others are formed at the cell surface

Question 21

Golgi apparatus

Answer 21

A group of fluid filled, membrane- bound, flattened sacs. Vesicles are often seen at the edge of the sacs

Question 22

Golgi apparatus function

Answer 22

Processes and packages new lipids and proteins

Also makes lysosomes

Question 23

Mitochondria

Answer 23

Usually oval-shaped
Double membrane, inner one is folded to form structures called cristae
Inside is matrix, contains enzymes involved respiration

Question 24

Mitochondria function

Answer 24

Site of aerobic respiration, where ATP is produced

They’re found in large numbers in cells that are very active (require a lot of energy).

Question 25

Chloroplast

Answer 25

Small, flattened structure found in plant cells Surrounded double membrane, also had membranes inside (thylakoid membranes) these membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae (thin flat pieces of thylakoid membrane)

Question 26

Chloroplast function

Answer 26

Site where photosynthesis takes place | Some parts of photosynthesis happen in the grana, and other parts in the stroma (a thick fluid found in chloroplast).

Question 27

Centrioles

Answer 27

Small, hollow cylinders, made of microtubules (tiny protein cylinders). Found in animal cells, but only some plant cells.

Question 28

Centrioles function

Answer 28

Involved with the separation of chromosomes during cell division

Question 29

Cilia

Answer 29

Small, hair like structures found surface membrane so animal cells Cross section, they have an outer membrane and a ring of nine pairs of proteins microtubules inside, with a single pair in middle

Question 30

Cilia function

Answer 30

Microtubules allow cilia to move. | Movement used by cell to move substances along cell surface

Question 31

Flagellum

Answer 31

Flagella on eukaryotic cells like cilia but longer. stick out from cell surface and are surrounded by the plasma membrane. Inside they're like cilia too (structure)

Question 32

Flagellum function

Answer 32

Microtubules contract, make flagellum move. | Flagella used like outboard motors to propel cells forward

Question 33

Organelles bacteria cells have

Answer 33

``` Free floating DNA (bacteria chromosomes) Flagellum Plasmids (rings of DNA) Cell wall Plasma membrane Ribosomes ```

Question 34

Give differences between prokaryotic and eukaryotic cells (7)

Answer 34

Extremely small / Larger cells DNA circular / DNA linear No nucleus (free floating) / Nucleus present Cell wall made polysaccharide / none for animal, cellulose for plants, chitin for fungi Few organelles and none membrane bound / many organelles and some membrane bound Flagella (when present) made protein flagellin, arranged in a helix / when present made microtubules in 9 + 2 formation Small ribosomes / Larger ribosomes

Question 35

Give two examples of dyes we can use

Answer 35

Methylene blue | Eosin

Question 36

In a light microscope why can we see an image

Answer 36

An image is produced because some parts of the object absorb more light than others.

Question 37

Why do we stain

Answer 37

Sometimes the object being viewed is completely transparent, so use a stain

Question 38

What's an eyepiece graticule and how is it used

Answer 38

It's fitted into the eyepiece, it's like a transparent ruler with numbers, but no units. So when you look down you will see a scale

Question 39

What's stage micrometer and how is it used

Answer 39

Placed on the stage, it's a microscope slide with accurate scale (has units) Used to work out the value of the division on the eyepiece graticule at a particular magnification

Question 40

Resolution

Answer 40

It's how well a microscope distinguishes between two points that are close together.

Question 41

Comparing types of microscope

Answer 41

Light microscope, max resolution: 0.2 micrometers, max magnification: x1500 TEM, 0.002 micrometers, can be more than x1000000 SEM, 0.02 micrometers, usually less than x500 000

Question 42

Electron microscopes

Answer 42

Use electrons to form an image | They have higher resolution than light microscopes and so give more detailed images

Question 43

TEM

Answer 43

Transmission electron microscopes | They use electromagnetic to focus a beam of electrons, transmitted through specimen to give a 2D image

Question 44

SEM

Answer 44

Scanning electron microscope Scan a beam of electrons across the specimen, knocking off electrons from specimen, which is gathered in cathode ray tube to form an image (3D)

Question 45

Cytoskeleton

Answer 45

Cytoplasms has got a network of protein threads running though it (called the cytoskeleton) In eukaryotic cells the protein threads arranged as microfilaments (very thin protein strands), and microtubules (tiny protein cylinders)

Question 46

Cytoskeleton function (4)

Answer 46

Microtubules and microfilaments support cells organelles (keeps them in position) Help strengthen the cell and maintain its shape Responsible for transport of organelles and materials within cell The proteins of the cytoskeleton can cause cell to move