IB Biology D3 3 Homeostasis Question Bank

A1. (a) higher BMI increases risk of type II diabetes / risk increases as the BMI increases; greater risk for women than for men / men have a lower risk than women; values above \(25 \mathrm{~kg} \mathrm{~m}^{-2}\) increase the risk of diabetes exponentially / BMI below \(25 \mathrm{~kg} \mathrm{~m}^{-2}\) shows minimal risk;

21 % (allow answers in the range of 20 % to 22 % )

indicated by marks on the graph on the vertical axis or on the line (allow 1 % error of the woman 8 % to 33 % at either end) Information must be indicated on the graph.

moderate portions of food to avoid fluctuations in blood sugar levels; regular mealtimes to avoid fluctuations in blood sugar levels; include unrefined carbohydrates because they are more (accept reverse for slowly absorbed; refined) include carbohydrates with a low glycemic index; (accept reverse for high) include fibre-rich foods to slow absorption of sugar; limit saturated/trans fats/cholesterol because diabetes increases risk of coronary heart disease;

type 1 caused by destruction of insulin secreting cells/beta cells (in pancreas) / insufficient insulin produced / genetic disorder resulting in failure to produce insulin; type II caused by decreased response of body cells/receptors to insulin (that is produced); type I early onset while type II adult onset; type I treated with insulin while type II with diet (lifestyle changes);

all ethnic groups show range (very high, high and normal) of albumin levels; greatest frequency of very high levels of albumin found in Pacific Islander patients/ European ancestry patients have lowest frequency of very high levels of albumin; greatest frequency of high levels of albumin in Indigenous Australian/European ancestry patients / lowest frequency of high levels of albumin in Pacific Islander patients; European ancestry patients have highest frequency of normal levels of albumin / Indigenous Australian/Pacific Islander patients have lowest frequency of normal levels of albumin;

European ancestry patients have highest/higher frequency of kidney failure but more than half/a large percentage have a normal level of albumin; Indigenous Australian patients have lower frequency of kidney failure but higher levels of albumin; it would be better to test for both kidney failure and albumin levels;

\(\left.\begin{array}{l}\text { 1. (a) type I: European / E } \\ \text { type II: Native American / NA }\end{array}\right\}\) (both needed) [1]

(accept range) 18-20 (cases per 100000) [1]

type I shows same/similar pattern of rate in both age groups; rates of type II were (much) greater among those aged 10-19 years than <10 years;

increased insulin concentration causes more glucose absorption (up to \(10^{3} \mu \mathrm{U} \mathrm{ml}^{-1}\) ); glucose absorption in muscle bathed in lipid always less than control; no further increase/slight decrease in glucose absorption beyond \(10^{3}\left(\mu \mathrm{U} \mathrm{ml}^{-1}\right)\) insulin;

Referring to first graph: plasma lipids lower activity of enzyme (needed for glucose absorption); Referring to second graph: more/higher glucose uptake with higher insulin levels in muscles without lipids (compared to muscles bathed in lipids); lipids reduce glucose absorption (even at raised insulin concentrations); isolated muscle used in experiments so results may differ in whole organisms;

glucose-fed group has no/little increase in triglycerides while fructose-fed group has a (large) increase; glucose-fed group has smaller variability than the fructose-fed group; more triglycerides in fructose-fed group than glucose-fed group (from week 2 to week 10);

raised blood glucose/sugar levels/higher glucose in the urine; decreased glycogen; excess glucose will be converted to fat/increase obesity; possibility of developing diabetes type II/ (do not award this mark if answer late/adult onset diabetes; (refers to type 1 diabetes)

vasoconstriction of skin arterioles so less blood flows to the surface to prevent heat loss from blood; hypothalamus control with thermoreceptors/hormones to increase/decrease metabolism; layers of fat under the skin/insulating fur to conserve body heat; shivering to generate heat; Accept other verifiable mechanisms explained.

similar/same/nearly same (means)/very small difference/both at a low level; b. means/averages (all) close to \(0.8 \mathrm{mg} \mathrm{ml}^{-1}\); c. difference not (statistically) significant; d. similar/same/nearly same range of values/spread of data; All marking points are comparisons between control and IKO mice. Do not award marks for comparisons between male and female mice.

a. in young mice/3 month old mice lack of FoxO1/IKO/fewer beta cells does not affect/has little effect on blood glucose/sugar; b. in older females/aging males blood glucose/sugar (much) higher with lack of FoxO1/IKO/fewer beta cells;

Award [1] for an answer: a. accept either 35 / 34.8 / 34.78 (this answer may be expressed as negative) OR 53 / 53.3 / 53.33; Do not award the mark if more than two decimal places shown or if the answer is incorrectly rounded up or down. Award [1] for working, accepting any of the following: b. 2.3-1.5 OR 1.5-2.3 \(\mathbf{OR}\left(\frac{(2.3-1.5)}{2.3}\right) \times 100\) \(\mathbf{OR}\left(\frac{1.5}{2.3}\right) \times 100=65 / 65.2 / 65.22 \%\) OR other credible alternatives for working;

lack of FoxO1 (correlates) with low/decreased insulin and high/increased glucagon levels

a. insulin used to take up/reduce glucose levels (after eating/when blood glucose levels high); b. decrease in insulin in FoxO1 lacking/IKO mice would cause increase in glucose levels (as less is removed); c. glucagon (used to convert stored carbohydrate to glucose) to increase glucose levels; d. increase in glucagon(as seen in second graph, where IKO level higher than control) would mean more glucose added to blood/increase in glucose levels (on first graph); e. (on first graph) see older/stressed/adult female mice with much higher glucose levels than young mice;

similar/same/nearly same (means)/very small difference/both at a low level; means/averages (all) close to \(0.8 \mathrm{mg} \mathrm{ml}^{-1}\); differences not (statistically) significant; similar/same/nearly same range/spread of data; All marking points are comparisons between control and IKO mice. Do not award marks for comparisons between male and female mice.

stress causes increase (in mean blood glucose/sugar); older mice/males/females / aging mice show the increase; Reject answers that only compare control and IKO mice or only compare male and female mice.

in young mice/3 month old mice lack of FoxO1/IKO/fewer beta cells does not affect/has little effect on blood glucose/sugar; in older females/aging males blood glucose/sugar (much) higher with lack of FoxO1/IKO/fewer beta cells;

Award [1] for an answer: accept either 35 / 34.8 / 34.78 (this answer may be expressed as a negative) OR 53 / 53.3 / 53.33; Do not award the mark if more than two decimal places shown or if the answer is incorrectly rounded up or down. Award [1] for working, accepting any of the following: 2.3-1.5 OR 1.5-2.3 \(\mathbf{OR}\left(\frac{(2.3-1.5)}{2.3}\right) \times 100\) OR \(\left(\frac{1.5}{2.3}\right) \times 100=65 / 65.2 / 65.22 \%\) OR other credible alternatives for working;

lack of FoxO1 (correlates) with low/decreased insulin and high/increased glucagon levels

newly formed \(\beta\) cells Accept if newly formed beta cells in IKO mice but not in control mice only. Reject all answers apart from the first given and any comparisons between IKO and control mice, rather than between younger and older mice.

All marking points are deductions based on comparing older females with 3 month females and on the assumption that any changes in \% are due to aging. newly formed \(\beta\) cells fewer/reduced/smaller \% (in control/IKO mice); cells still producing insulin (slightly) more/increased/higher \% in controls; cells still producing insulin fewer/reduced/smaller \% in IKO mice; cells no longer producing insulin only in older IKO mice; Accept answers where IKO mice are referred to as mice without FoxO1 and control mice are referred to as mice with FoxO1.

supported in older IKO mice/older mice lacking FoxO1 by: cells no longer producing insulin present (only) in older IKO mice/mice lacking FoxO1; (type 2) diabetes/high blood glucose/lower insulin in older IKO mice/mice lacking FoxO1; not supported by: lower mass of \(\beta\) cells in older IKO mice/mice lacking FoxO1; no drop/small rise/small change in cells producing insulin in older control mice; Candidates must make it clear in their answer to ( h ) whether the data is in support of the hypothesis or against. Evidence can be included for and against. Answers should specify whether the data is from older IKO mice or from older control mice. If the age is not specified in the answer, penalise for one of the marking points but not any others.

470 Accept answers in the range of 460 to 480 « \(m g d L^{-1}\) ».

a. «autoimmune» destruction of beta/ㅡㅡ cells b. reduced/insufficient/no production of insulin Accept B cells instead of \(\beta\) cells. 1 max

a. decrease in transplant group «after treatment» in contrast to control group which does not decrease/decreases only very slightly «initially»/increases/is higher than treatment group b. glucose «remains» lower in transplant group «than control group» for 2 weeks/ 3 weeks/for a time c. «in the \(4^{\text {th }}\) week» transplant group rises back to level before transplant/to higher level than before transplant/to «near» level of control group The answer must include some indication of time or non-permanency. 2 max

a. glucose level still higher than normal/higher than 100 «mg»/higher than it was before the drug injection b. effective/lowers blood glucose for 3 weeks/temporarily/for a short time OR glucose level rises back in \(4^{\text {th }}\) week/by day 28 OR rises back to level of control group OR rises again but not above control group This can either be positive (the treatment is effective for a while) or negative (it isn't effective permanently). There must be a correct indication of the timing of the effects.

700 No other answer accepted.

a. C-peptide increases after treatment in both groups OR treatment effective in both groups OR both groups rose higher than the control b. similar/same overall/total increase «in both groups» OR quoted figures to show this c. smaller percentage/\% increase «pre to post treatment» in group 1 «than group 2» OR quoted figures to show this d. initial increase is greater in group 1 OR increases slowing/finished/rate of increase reduced by end of study/by week 24 in group 1 but continuing in group 2 e. group 1 rose above lower limit «by week 12» and group 2 remained below it «even at week 24 » There must be an explicit comparison. Reject answers relating to rates of increase. 3 max

a. study 1 / study with mice/embryonic stem cell study shows treatment can cause increased insulin production/ reduce blood glucose levels b. «insulin production/reduction in blood glucose in study 1 was» only temporary/did not reduce glucose to normal levels c. study 2 shows increases in C-peptide/insulin OR some type I diabetes patients required no insulin after treatment d. study 2 shows treatment effective for a long time/ 2 years e. «stem cell treatment in study \(2 »\) was more successful in some patients than others OR more successful for moderate «than more severe» diabetes f. study 3 shows that stem cells can cause C peptide/insulin levels to double/rise significantly/rise above lower limit «for normal C-peptide»/rise and stay raised g. «study 3» does not give evidence for embryonic stem cells OR used umbilical cord rather than embryonic stem cells Strength Limitation Strength Strength Limitation Strength Limitation 4 max