from pp

Question 1

how do the characteristics of inflammation help in response

Answer 1

• pain alerts the person that there is an injury
• warmth speeds up {chemical reactions / skin cell division
  / phagocytosis / increases rate of enzyme activity (of
  person) / defence mechanisms}
• swelling results in more {blood / white blood cells /
  platelets / phagocytes / antibodies/ tissue fluid} (to the
  wound)
• redness results in more {blood / white blood cells /
  platelets / phagocytes / antibodies} (to the wound)

Question 2

what is the difference between bactericidal and bacteriostatic antibiotics

Answer 2

bacteriostatic inhibit the growth of bacteria in other words keeps the number of bacteria constant
bactericidal antibiotics destroy the bacteria in other words decrease the number of bacteria

Question 3

how does gut flora (bacteria in the intestines)

Answer 3

• to compete with pathogenic bacteria for nutrients/space which would limit the growth of pathogenic bacteria

Question 4

define habitat

Answer 4

• a place organisms live

Question 5

define population

Answer 5

• organisms of one species living in a particular area

Question 6

define community

Answer 6

a group of organisms of different species interacting in a particular area

Question 7

calculation in investigation

Answer 7

• calculate the mean AND SD

Question 8

define anthropogenic

Answer 8

• caused by effects of humans
• changes to mean temp.

Question 9

how to calculate the age of a tree by the rings

Answer 9

• each year a ring will form
• the thickness of the rings will be different each year depends on the condition

Question 10

define aseptic technique

Answer 10

• methods used to prevent contamination of culture

Question 11

why using aseptic technique is important

Answer 11

• prevent the entry of bacteria that may compete with E.coli
• to prevent infection of the person with bacteria in culture that may be pathogenic

Question 12

define biodiversity

Answer 12

• number of different species
• genetic diversity within a specie

Question 13

state the meaning of the term biomass

Answer 13

how much organic matter present in organisms

Question 14

why describe diagrams as model

Answer 14

because it is making predictions (1)

 based on {knowledge / data} (1)

 it is a visual representation (of what might happen) (1)

Question 15

why are enzymes needed

Answer 15

• needed for metabolism

Question 16

why two primers are needed in PCR

Answer 16

primers needed so that (DNA / taq) polymerase can bind (to
one strand)

because one primer is needed for each strand

because the DNA strands {are antiparallel / are
complementary / have different base sequences at each end}

Question 17

how does TB result in death

Answer 17

• because formation of tubercles
• therefore insufficient oxygen for aerobic respiration
• organ failure
• weakens immune system so death from infection

Question 18

how optical methods can be used to compare the growth rates of two populations

Answer 18

• both types of bacteria cultured in the same culture conditions
• use aseptic technique
• use light meter / light sensor
  / spectrophotometer /
  colorimeter / cross
  underneath the flask / shine a
  light through and measure
  {transmission / absorbance}
• calibration curve used to determine concentration of bacteria

Question 19

what are interferons

Answer 19

• interferons are secreted by infected cells (1)
   they are anti-viral proteins (1)
   preventing {viral replication / synthesis of viral proteins /
  spread of virus} (1)
   involved in activation of {macrophages / T killer cells}

Question 20

what happens to the bacteria at the lag phase

Answer 20

• (no increase in number of bacteria) because the cells had to
  {adjust to new environment / warm up / synthesise new
  enzymes}

Question 21

log

Answer 21

(increase in number of bacteria) as {conditions are suitable /
nutrients available / pH appropriate / oxygen levels
appropriate / appropriate temperature}

Question 22

describe the method used in dilution plating

Answer 22

• use serial dilution
• sample added to agar and spread

Question 23

state the characteristics of pioneer species

Answer 23

need to withstand {harsh / extreme} environments (1)
* need to be able to withstand {dessication / lack of shade} (1)
* have a low requirement for {minerals / mineral ions / named
mineral ion / soil}
* have {fast life-cycles / grow fast / reproduce asexually / produce lots
of seeds / wide dispersal mechanisms}

Question 24

why succession occurs in stages

Answer 24

changes to the habitat have to take place before a different
organism can survive there
* credit named improvement g. make soil, improve soil,
provide food (for animals)
* credit organism that would appear in next stage following this
improvement e.g. (deeper soil) bushes / trees,
(food / shelter) animals

Answer 25

nuclear DNA is linear and mtDNA is circular (1)
* nuclear DNA has unbound {phosphate group / sugar} whereas
mtDNA does not (1)
* mtDNA has (far)fewer {phosphodiester bonds / base pairs}