Chapter 2

Question 1

What is a light microscope

Answer 1

A light microscope uses like to achieve and magnification of up to 1500 times and the resolution of up to 0.2 micro metres which allows us to see individual cells and some organelles within them

Question 2

What is a transmission electron microscope?

Answer 2

The transmission electron microscope uses electromagnets to focus a beam of electrons through a specimen producing an image up to 1 million times magnification and 0.0002 Micro metres which allows us to see more details of cell ultrastructure

Question 3

What is a scanning electron microscope?

Answer 3

A scanning electron microscope is a beam of electrons that are sent across the surface of the specimen and the reflecting electrons are collected to produce a 3-D image with up to 500,000 times magnification and zero. 002 micro metres resolution

Question 4

What is a laser scanning confocal microscope?

Answer 4

Laser scanning confocal microscope is a type of light microscopy that uses laser is to scan a specimen treated with a fluorescent die and the detector to produce a 2-D or 3-D image which is much clearer than a light microscope

Question 5

How do you prepare a dry mount?

Answer 5

1) section a small slice of the specimen
2) put it on a slide
3) put a cover slip on it

Question 6

How do you prepare a wet mount?

Answer 6

1) put a drop of water on the slide
2) place your specimen on the drop
3) place on the cover slip at an angle

Question 7

How do you prepare smear slides?

Answer 7

1) put a drop of specimen on the slide
2) use the edge of another slide to smear it
3) place a cover slip on it

Question 8

How to use a microscope

Answer 8

1) clips slide onto stage
2) select lowest power objective lens
3) focus using coarse then fine adjustment knob
4) use a higher power lens then re focus

Question 9

How to use an eyepiece graticule and stage micrometer

Answer 9

1) line up the eyepiece graticule and stage micrometer

2) work out the size of one eyepiece graticule division

Question 10

Magnification=

Answer 10

Magnification= image size/ object size

Question 11

7 rules of scientific drawings

Answer 11

1) title
2) magnification
3) fill the space
4) label lines are parallel to page
5) no arrow heads
6) no shading
7) continuous lines

Question 12

Definition of a eukaryotic cell

Answer 12

A complex cells containing a membrane-bound nucleus in which genetic information is stored

Question 13

Cell wall

Answer 13

Made of Celulose and supports the cell

Question 14

Centrioles

Answer 14

Hollow cylinders made up of microtubules which separate chromosomes during cell division

Question 15

Plasma membrane

Answer 15

Made up of lipids and proteins regulate substance movements and contains receptor molecules for cell communication

Question 16

Chloroplasts

Answer 16

Have a double membrane and internal thylakoids membranes which when stacked are called grana and contain fluid called stoma – they are the site of photosynthesis

Question 17

Lysosome

Answer 17

A lysosome is a membrane-bound structure responsible for breaking down waste material and pathogens ingested by phagocytes

Question 18

Mitochondria

Answer 18

The mitochondria are the sight of the final stages of respiration they have a double membrane- the inner one is folded into structures called Cristae And inside is the fluid matrix.

Question 19

Ribosomes

Answer 19

Ribosomes are the site of protein synthesis and are made up of proteins and RNA

Question 20

Golgi apparatus

Answer 20

Golgi apparatus is a group of membrane-bound sacs responsible for processing and packaging lipids and proteins and also for making lysosomes

Question 21

Smooth endoplasmic rectilum

Answer 21

The smooth endoplasmic rectilum The network of membranes enclosing flattened sacs called cisternae responsible for lipids and carbohydrates synthesis and storage

Question 22

Rough endoplasmic rectilum

Answer 22

The rough endoplasmic rectilum Is a network of membranes enclosing flattened saves called cisternae that have ribosomes attached to its surface for protein synthesis and transport

Question 23

Nucleus

Answer 23

The nucleus contains the genetic information as DNA and controls most cells activities also contains chromatin

Question 24

Nucleolus

Answer 24

The nucleolus is an area within the nucleus composed of RNA and proteins which are used to create ribosomes

Question 25

Nuclear envelope

Answer 25

The nuclear envelope is a double membrane surrounding the nucleus which contains pores to control the movement of substances

Question 26

Cilia

Answer 26

Cilia are made up of microtubules in a 9+2 formation which move substances along the cell surface

Question 27

Flagella

Answer 27

Flagella Is also made up of microtubules in a 9+2 formation and used for cell mobility

Question 28

The interrelationship between the organelles in the production and secretion of proteins

Answer 28

1) Proteins are synthesised at the ribosomes on the rough endoplasmic reticulum
2) They pass into the cisternae of the rough endoplasmic reticulum where they are packaged into transport vesicles
3) The vesicles are transported to the Golgi apparatus via the cytoskeleton
4) At the Golgi apparatus they are processed further
5) Finally they are packaged into secretory vesicles to be transported out/around the cell

Question 29

What parts make up the cytoskeleton and what are their functions?

Answer 29

Microfilaments – contractile fibres formed of actin responsible for cell movement and support organelles
Microtubules – proteins Cylinders that determine the shape of a cell and act as tracks for the movement of organelles
Intermediate fibres – give mechanical strength to cells and help maintain their integrity

Question 30

What are the differences between eukaryotic and prokaryotic cells

Answer 30

Size – prokaryotic cells are one 10th of the size of eukaryotic cells
Reproduction – prokaryotic cells reproduce through binary fission whereas eukaryotic cells reproduce through a sexual/sexual reproduction
Prokaryotic cells have fewer organelles and no membrane-bound organelles
Prokaryotic cells have circular (not linear) DNA which is free-floating in the cytoplasm And extra chromosomal DNA
Prokaryotic cells have small ribosomes
Prokaryotic cells have a cell wall made of peptidoglycan