25 October, 1997

25 October 97

0500L SEVERE WEATHER CONDITION

CONDITION III for all locations.

REGIONAL WEATHER SUMMARY...Mostly sunny skies will grace the McMurdo area this morning. Clouds will move into the area late in the day as a weak low pressure system moves in with some light snow.

TODAY...Mostly sunny. A few periods of blowing snow possible on the sea ice this morning.

Visibility: Unrestricted, lowering to 5-7 miles in blowing snow on the sea ice this morning.

Wind (knots): Northeast 10 to 20.

High -8C/+18F. Lowest Wind-chill -22C/-07F

TONIGHT ...Cloudy with periods of light snow.

Visibility: Unrestricted, occasionally 3-6 miles in snow.

Wind (knots): East 15-20 occasional gusts to 25.

Low -12C/+10F Lowest Wind-chill -33C/-27F

SUNDAY...Cloudy with snow and blowing snow becoming frequent in the afternoon.

Visibility: Unrestricted lowering to 2-4 miles in snow/blowing snow in the afternoon.

Wind (knots): East-southeast 15-20.

High -10C/+14F Lowest Wind-chill tonight -30C/-22F.

SCOTT BASE 24HR TEMPERATURE FORECAST

High -09C. Low -15.

ASTRONOMICAL DATA

Next sunrise in February, 1998

YESTERDAY'S EXTREMES - 24 October, 1997

Maximum Temperature: -09C/+16F

Minimum Temperature: -12C/-10F

Peak Wind: 62 Knots

Lowest wind chill: -34C/-30F

I don't know what happened to today. No sooner had the day begun than it was getting late. For some reason I ran out of time. Yesterday I determined the respiration rate on individual starfish tube feet. I needed to run two additional experiments on this tissue so I froze the it for use today. After homogenizing each tube foot I took samples and ran an experiment to determine the amount of protein. This turned out very well and the protein concentrations are comparable to ones I was getting in my preliminary work. As things turned out this was the only experiment I had time for.

In addition to the protein data I need to do an experiment which will determine the activity of the enzyme, citrate synthase. This enzyme is used by cells in the process of getting energy from nutrients (cellular respiration). By measuring the activity of citrate synthase I will know the maximum activity this enzyme could have in tube feet cells. By doing these experiments at various temperatures I will be able to tell how citrate synthase activity changes relative to changes in the respiration rate

Things to ponder:

Mitochondria are structures found in cells which specialize in the chemical reactions of aerobic respiration. These reactions utilize oxygen while producing energy from the food we eat. One group of these chemical reactions is known as the Krebs Cycle (or Citric Acid Cycle). Citrate synthase is an enzyme which catalyzes one of the reactions of the Krebs Cycle.

1. Enzymes are biological catalysts. What is a catalyst anyway?

2. How do catalysts function in cells (i.e. what do they do)?

3. Read up on enzymes and find out how temperature affects them?

4. What is your prediction regarding the effect of temperature on citrate synthase activity?