Lab Exam Study

Question 1

What does the purple colour of the bacteria mean

Answer 1

Gram Positive

Question 2

What does the pink colour of the bacteria mean

Answer 2

Gram negative

Question 3

What shape is coccus

Answer 3

spheres

Question 4

what shape is basillus

Answer 4

rods

Question 5

what shape is spirrilum

Answer 5

spirals

Question 6

If the shapes are in doubles, the prefix _ is used

Answer 6

diplo

Question 7

f the shapes are in chains the prefix _ is used,

Answer 7

strepto

Question 8

If the shapes are in clusters, the prefix _ is used

Answer 8

staphylo-

Question 9

why does gram staining work

Answer 9

all bacteria cell walls have a compound called peptidoglycan. If they become purple from gram staining, they have a thick layer of peptidoglycan and are considered gram positive. If they are pink from gram staining, they have a thin layer of peptidoglycan and are considered gram negative

Question 10

How does staining gram-negative cells work

Answer 10

They have a thin layer of peptidoglycan, and they have an outer membrane composed of lipopolysaccharide. When we put alcohol on the bacteria, it dissolves the lipopolysaccharide and washes away the dye from the cell wall

Question 11

Why is gram-staining important

Answer 11

The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. to help identity bacteria present in a sample and to determine which antibiotics to use. Purple means gram positive, pink means gram-negative. Pink is generally more harmful.

Question 12

What does ELISA stand for

Answer 12

Enzyme-Linked Immunosorbant Assay

Question 13

What are antibodies

Answer 13

Antibodies are made by people in response to an antigen. They are Y-shaped proteins whose upper “tips” differ in their shapes

Question 14

What are antigens

Answer 14

Antigens are any part of an invader that triggers the production of antibodies.

Question 15

What is the relationship between antigens and antibodies

Answer 15

When antigens trigger the formation of antibodies, only those antibodies with the corresponding shape will be produced.

Question 16

What does a colour change in ELISA mean

Answer 16

Primary antibodies are present in patients blood

Question 17

How does an ELISA work? That is, what do the steps, in that order, do?

Answer 17

Microwells are provided that contain the antigens to specific diseases. These antigens are firmly stuck to the well (1). The patient’s blood serum is added to the well. If the blood serum contains antibodies that are specific to that antigen (called primary antibodies), they will attach to the antigens (2). Any excess material is washed off. The secondary antibodies are added and they will attach to the primary antibodies if primary antibodies are present. (These secondary antibodies are made from non-human animals and are designed to attach to human primary antibodies.) Secondary antibodies have an enzyme attached (3). Excess material is washed away.
The substrate specific to the enzyme is added. If the secondary antibody with the attached enzyme is present, the enzyme will convert the substrate into something else, causing colour change to occur. The stronger the colour change, the more antibodies are present (4).

Question 18

Describe the colour change for a positive benedicts test

Answer 18

Red: large amounts of glucose, Orange: moderate, green: trace, blue: non

Question 19

Describe the colour change for a positive buiret test

Answer 19

Purple: positive, No colour change: negative