Which side bonds must be broken chemically to change the natural curl pattern of hair permanently?
- Hydrogen bonds
- Disulfide bonds
- Salt bonds
- Peptide bonds
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B. Disulfide bonds
Disulfide bonds are the strong chemical side bonds; permanent waving and relaxing work by breaking them. Hydrogen bonds are broken by water alone, which only gives a temporary change such as a wet set.
Reference: Barbering theory: chemical services (chemistry of texture services)
Hair is built from the elements carbon, oxygen, hydrogen, nitrogen and sulfur. Which of these forms the cross-links of a disulfide bond?
- Carbon
- Nitrogen
- Oxygen
- Sulfur
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D. Sulfur
A disulfide bond joins the sulfur atoms of two cysteine amino acids on neighboring protein chains. Carbon is the most abundant element in hair, but it does not form these side bonds.
Reference: Barbering theory: properties and disorders of the hair and scalp (chemical composition)
What distinguishes a skin (bald) fade from other tapered cuts?
- The hair is left at a #2 guard length around the hairline
- The top is cut flat and level, like the bristles of a stiff brush
- The neckline is squared off with a hard line at the nape
- The hair blends all the way down to bare skin at the bottom
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D. The hair blends all the way down to bare skin at the bottom
In a skin fade the shortest area is taken to the skin and the length builds gradually upward with no visible line. A squared nape with a hard line is a blocked neckline, which is the opposite of a faded finish.
Reference: Barbering theory: men's haircutting (fades)
Streptococci, the bacteria responsible for strep throat, grow in which arrangement?
- Rounded clusters, like a bunch of grapes
- Pairs, joined two at a time
- Curved chains, like a string of beads
- Tight spirals, like a corkscrew
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C. Curved chains, like a string of beads
Streptococci are pus-forming cocci that line up in curved chains. Clusters describe staphylococci, which cause boils, pustules and abscesses, so the two are easy to mix up.
Reference: Barbering theory: infection control and safe work practices (bacteriology)
Which razor position and stroke is used on more of the standard shaving areas than any other?
- Backhand
- Reverse freehand
- Reverse backhand
- Freehand
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D. Freehand
The freehand stroke is the basic stroke and covers the largest share of the 14 areas. The reverse backhand is the least used; it is kept mainly for outline work on the left side with the client sitting up.
Reference: Barbering theory: shaving (razor positions and strokes)