2- Baisc components of living systems

Question 1

How do you produce a good scientific drawing?

Answer 1

-title
-state magnification
-use a sharp pencil for drawings and labels
-white, underlined paper
-use as much of the paper as possible for the drawing
-smooth continuous lines
-don’t shade
-clearly defined structures
-correct proportions
-labels should not cross or have arrow heads
-labels parallel with. top of page

Question 2

What are the two types of electron microscope?

Answer 2

Transmission electron microscope
Scanning electron microscope

Question 3

What is the transmission electron microscope, how does it work, what are is its maximum range?

Answer 3

-Shoots a beam of electrons at a thin slice of sample and detecting those electrons that make it through to the other side
-Magnification X500,000
-Resolution 0.5-2nm
-Let’s us look at sample in high resolution, good for learning about components inside cell

Question 4

What is a scanning electron microscope, how does it work, what are its maximum values?

Answer 4

-A beam of electrons is sent across the surface of specimen and the reflected electrons are collected
-Produces 3D image
-Samples do not have to be thin/cross sections
-Magnification X100,000
-Resolution 3-10 nm
-Require a vacuum as air particles would intervene with beam of electrons so specimen must always be dead

Question 5

What is a light microscope, how does it work and what are its maximum values?

Answer 5

-2 lenses
-Objective lens produces a magnified image
-Eyepiece lens magnifies it again
Easy to use
-Cheap
-Samples must be thin to allow light to pass through
-Stain is used to see structures more visibly
-Magnification X15,000
-Resolution X200nm

Question 6

How do you calibrate a light microscope?

Answer 6

1. Put the stage micrometer in place and the eye piece graticule in the eyepiece
2. Get the scale on the micrometer slide in clear focus
3. Align the micrometer scale with the scale in the eyepiece. Take a reading from both scales
4. Calculate the length of one eyepiece unit

ASK MISS

Question 7

What is a stage micrometer?

Answer 7

A microscope slide with very accurate scale in micrometers engraved on it

Question 8

What is an eyepiece graticule?

Answer 8

A glass disc marked with a fine scale of 1-100. The scale has no units

Question 9

Why is staining used in light microscopy?

Answer 9

Stains increase contrast which allows components to become visible.

Question 10

What is differential staining?

Answer 10

Used to distinguish between two types of organism that would otherwise be hard to identify. Can also distinguish between different organelles of a single organism within a tissue sample

Question 11

What is the equation for magnification?

Answer 11

magnification = size of image/ actual size of object

Question 12

What is resolution?

Answer 12

The ability to see individual objects as separate entitles

Question 13

What is magnification?

Answer 13

How many times larger the image is then the actual size of a object being viewed

Question 14

What are the 7 characteristics of life?

Answer 14

movement
Reproduction
Sensitive
Growth
Respire
Excrete
Nutrition

Question 15

what is the function of the cell surface membrane?

Answer 15

Control the movement of substances in and out of the cell

Question 16

what is the function of the Golgi apparatus?

Answer 16

Modify and package proteins into vesicles

Question 17

What is the function of ribosomes?

Answer 17

-can be free floating in cytoplasm or attach to the RER
-No membrane
-Site of protein synthesis

Question 18

what is the function of the mitochondria?

Answer 18

Sight of final stages of cellular respiration
Production of ATP by aerobic respiration

Question 19

what is the function of the rough endoplasmic reticulum?

Answer 19

-Ribosome is bound to its surface
-Interconnected, flatten sacs
-Synthesis and transport of proteins

Question 20

What is the function of the smooth endoplasmic reticulum?

Answer 20

Lipids and carbohydrates, synthesis and storage

Question 21

what is the function of lysosomes?

Answer 21

-Specialise forms of vesicles
-Contain hydrolytic enzymes
-Breakdown waste material, in cells
-Important in the immune system as break down pathogens
-Important role in programmed cell death 

Question 22

what is the function of chloroplast?

Answer 22

-responsible for photosynthesis in plants cells
-Found in cells in the green parts of plants 

Question 23

what is the function of the nucleus?

Answer 23

-contains genetic information wrapped around proteins

Question 24

what is the function of a nuclear envelope?

Answer 24

-Contains nuclear pores which allow molecules to move in and out of the nucleus
-Double membrane
-Protect DNA from damage in cytoplasm

Question 25

what is the function of the nucleolus?

Answer 25

-Produces ribosomes
-Composed of proteins and RNA

Question 26

what is the function of the centrioles?

Answer 26

create a spindle fibres and are used for the separation of chromosomes during cell division. Not in plants.

Question 27

What is the function of the cell wall?

Answer 27

-made of Cellulose
-Freely permeable, so substances can pass in and out
-Give the plant sheep
-Defence mechanism protecting content of the cell against invading pathogens

Question 28

What is the function of vacuoles?

Answer 28

-membrane lined, sacs in the cytoplasm
-Contains cell sap
-Important in the maintenance of turgor, so that the contents of the cell push against the cell wall and maintain a rigid framework for the cell

Question 29

What is the function of cilia?

Answer 29

-hair like organelles that extend from surface of certain cells
-beat in waves
-can sense chemicals around cell

Question 30

what is the function of the flagella?

Answer 30

-whip like organelle
-role is to move the cell

Question 31

what is the structure and function of the cytoskeleton?

Answer 31

-present throughout the cytoplasm in eukaryotic cells
-network of fibres necessary for the shape and stability of a cell
-organelles are held in place by the cytoskeleton and it controls cell movement and movement of organelles within cells

has 3 components
MICROFILAMENTS- contractile fibres formed from protein actin. Responsible for cell movement and also cell contraction during cytokinesis
MICROTUBLES- globular tublin proteins polymerise to form tubes that are used to form scaffold like structures that determines the shape of the cell. Act as tracks for movements of organelles.
INTERMEDIATE FIBRES- give mechanical strength to cells and help maintain their integrity

Question 32

how is protein synthesised? And through what organelles?

Answer 32

1. Proteins are synthesised on the ribosome is bound to the endoplasmic reticulum.
2. They are then packaged into transport vesicles. Vesicles containing the newly synthesise proteins move towards the gogli apparatus via the transport function of the side to skirting
3. The vesicles fuse with this cis face of a gogli apparatus and proteins enter
4. Proteins and modified before leaving the Gogli apparatus in vesicles from its trans-face
5. Secretory vesicles carry proteins that are to be released from the cell. The vesicles move towards an fuse with the cell surface membrane, releasing their contents by exocytosis. Some vesicles form lysosomes - these contain enzymes for use in the cell

Question 33

what are the similarities and differences between prokaryotic and eukaryotic cells?

Answer 33

-P cells have no nucleus and E cells have a nucleus
-P cells have circular DNA, E cells have linear DNA
-P cells have no membrane bound organelles, E cells have both membrane and non-membrane
-P cells have a peptidolyglycan cell wall, E cells have chitin in fungi, cellulose in plants, not present in animals
-P cells have smaller ribosomes (70S) , E cells have larger ribosomes (80S)
-P cells and E cells have a present cytoskeleton but E cells are more complex
-P cells reproduce by binary fission, E cells reproduce by asexual or sexual reproduction
-P cells are unicellular, E cells are unicellular and multicellular
-Both P and E cells have a present cell surface membrane