11.1b Defense Against Disease
19/11/2013 § Leave a comment
DATA BASED QUESTIONS
1. Describe how the ability of a calf to absorb antibodies changes over the initial hours after birth. –> As time passes, the amount of antibodies absorb decreases. The decrease of antibodies is steep from 0 to about 4 hours, then less steep from 4 to 23-24 hours and afterwards, the decrease is almost like a plateau.
2. Suggest reasons for calves that have endured a long and difficult birth are more likely to suffer from infection. —> These calves are more prone to infection because of too much passing time. Not having antibodies present makes them more vulnerable to infections.
3. Predict how the concentration of antibodies might vary in the cow’s colostrum over the first 24 hours after birth. –> After 24 hours, the concentration of antibodies starts decreasing.
4. Deduce the reasons for vaccinating sheep against pulpy kidney and other life-threatening diseases three weeks before lambs are due to be born. –> Three weeks is the right amount of time to keep antigens in the body when the lambs first start nursing.
5. Explain which method of transport across membranes is likely to be used for absorption of antibodies in the stomach of newborn mammals. –> Since antibodies are large molecules (proteins), diffusion wouldn’t be enough to get them across a membrane, so they’d do active transport.