biology a chapter two powerpoint

Aim: What is Aim: What is homeostasis?homeostasis?

Do Now: On your paper.Do Now: On your paper.

Notes are in Notes are in yellowyellow..

Words to know…Words to know…Maintain – keep up.Constant – the same.Internal – inside the body.Environment – surroundings of the

body.

What is Homeostasis?What is Homeostasis?Body cells work best if they have the correctTemperatureWater levelsGlucose concentration

Your body has mechanisms to keep the cells in a constant environment.

What is Homeostasis?What is Homeostasis?

The maintenance of a constant environment

in the body

In Other Words...In Other Words...The weather report from inside your body is ALWAYS THE SAME.

Controlling body temperatureControlling body temperature• All mammals and birds maintain a

constant body temperature. Human beings have a body

temperature of about 98.6 ºF. If your body is in a hot environment

your body temperature is 98.6 ºF If your body is in a cold environment

your body temperature is still 98.6 ºF

What mechanisms are there to What mechanisms are there to cool the body down?cool the body down?

1. Sweating

Sweating

The skin

What mechanisms are there to What mechanisms are there to coolcool the body down? the body down?

2. Enlargement of the blood vessels There are capillaries underneath

your skin that expand if hot. This brings the blood closer to the

surface of the skin so more heat can be lost.

This is why you look red when you are hot!

If the temperature rises, the blood vessel dilates (gets bigger)

This means more heat is lost from the surface of the skin

What mechanisms are there to cool What mechanisms are there to cool the body down?the body down?

3. PantingSimilar to sweating

Panting

What mechanisms are there to What mechanisms are there to warm the body up?warm the body up?

1.Shrinking of the blood vessels The capillaries underneath your skin

get constricted (smaller). This takes the blood away from the

surface of the skin so less heat can be lost.

If the temperature falls, the blood vessel constricts (tightens)

This means less heat is lost from the surface of the skin

What mechanisms are there to What mechanisms are there to warm the body up?warm the body up?

1.Goosebumps The hairs trap a layer of air next to

the skin which is then warmed by the body heat

Does NOT work in humans. Why?

• Shivering Shaking muscles generate

heat

What mechanisms are there to What mechanisms are there to warm the body up?warm the body up?

Wrap-Up!Turn to the chapter 2 word wall on page 53.Record at least two “new to you” words that we used in class today.

Aim: How do Aim: How do disease and stress disease and stress affect homeostasis?affect homeostasis?

Do Now: On your paper.Do Now: On your paper.

Notes are in Notes are in yellowyellow..

Controlling Glucose levels• Your cells also need an exact level of

glucose in the blood. This is regulated by 2 hormones from

the pancreas called:

InsulinGlucagon

If there is too much glucose in the blood, Insulin converts some of it to glycogen

Insulin

Glucose in the blood

Glycogen

If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose.

Glycogen

Glucagon

Glucose in the blood

DiabetesDiabetesPeople with diabetes do not produce enough insulin.

When they eat food, the glucose levels in their blood cannot be reduced.

Diabetics sometimes have to inject insulin into their blood. They have to be careful of their diet.

The glucose in the blood increases.

Glycogen

Glucose in the blood

But there is no insulin to convert it into glycogen.

Glucose concentration rises to dangerous levels.

Insulin

Time

Glucose Concentration

Meal eaten

Insulin is produced and glucose levels fall to normal again.

Glucose levels rise after a meal.

Time

Glucose Concentration

Meal eaten

Insulin is not produced so glucose levels stay high

Glucose levels rise after a meal.

Ben’s Bad Day

http://ats.doit.wisc.edu/biology/ap/ho/t1.htm

Wrap-Up!Turn to the chapter 2 word wall on page 53.Record at least two “new to you” words that we used in class today.

Aim: What is the metric system, and why do we use it?

Notes are in Yellow.

Do Now: On your paper

30ºC = 86 ºF 35 km = 21 miles

What Type of Measurement do we Normally Use in the USA?• The “English System”•Why don’t we use this system in science? • Too complicated, no logic

How Complicated Is It?

• 12 inches in a foot• 3 feet in a yard• 16 ½ feet in a rod• 120 feet in a furlong• 2 pints in a quart• 4 quarts in gallon• 2 gallons in a peck• 4 pecks in a bushel

WTFudge?• There is no logic so you can’t guess the relationship.

• If you want to use the English System, you have to memorize the relationships and multiply or divide to do conversions

• Luckily, the metric system is MUCH easier!!!

How is the Metric System Easier?

• In the metric system, everything is based on units of 10.

• Every type of measurement uses the same beginning prefixes.

• We can do conversions WITHOUT doing math, just by moving the decimal point right or left.

What is the Basic Unit for Length?Meter abbreviated as m • How long is a meter?• A meter is about a yard. (39.37 inches - a yard is 36 inches)

What is the Basic Unit for Volume?Liter abbreviated as L • How much is a liter?• A liter is about a quart. (1.06 quarts)

What is the Basic Unit for Mass/Weight?Gram abbreviated as g • How much is a gram?• A gram is very light – about the weight of a paperclip! (0.035 ounces)

• Would a meter stick be good enough unit to measure a hair?

• No, it’s too big• If you wanted to measure the distance from the earth to the sun, would a meter stick be a good way to measure the distance?

• No, it’s too short• Need smaller and larger units

Using the Metric System

Use Prefixes to Make Units Bigger or Smaller

• Centi – what does this mean? • 1/100 or 0.01 -makes unit smaller

• Milli – what does this mean? • 1/1000 or 0.001 -makes unit smaller

• Kilo – what does this mean? • 1000 - makes unit larger

Conversions are EASY! Let’s Practice!

• A) 9 0 g = _____ kg• B) 3.0 L = _____ mL • C) 5.0 m = _____ cm

0 0 0 0 0 0 0.009.

Conversions are EASY! Let’s Practice!

• A) 9 0 g = _____ kg• B) 3 0 L = _____ mL • C) 5.0 m = _____ cm

0.0 0 0 0 0 0.009.0 0 0 0 0 0. 3000

Conversions are EASY! Let’s Practice!

• A) 9 0 g = _____ kg• B) 3 0 L = _____ mL • C) 5 0 m = _____ cm

0.0 0 0 0 0 0.0090 0 0 0 0 0. 30000 0 0 0 0 0. . 500

Wrap-Up!Turn to the chapter 2 word wall on page 53.Record at least two “new to you” words that we used in class today.

Aim: What are microscopes and how do we use them?

Do Now: on your paper

Notes are in RED.

Types of MicroscopesOptical Microscope: Uses lenses to magnify an object.

Dissecting Microscope: Magnifies objects that are too thick for other types. Used to look at whole organisms.

Electron Microscopes: Gets much higher resolutions. Very expensive and only used at universities

In high school, the microscope that you will be using is the optical microscope.

Which type of microscope?A.

B.

C.

Robert Hooke- 1663Was using a primitive simple microscope –

consisted of a few lensesLooked at a piece of cork He saw a bunch of little boxes in the corkMade up the word “cell” since he thought each

box looked like a room in a monastery (which were called “cells”)

Antony van Leeuwenhoek- 1673

Ground Lenses together- more efficient than Hooke

Looked at pond water and saw organisms that he called “animicules” (tiny animals)

Now we use the word “microorganisms.” Was the first

person to observe muscle fibers, bacteria, sperm cells, and blood flow in capillaries.

Some Things to RememberNEVER use the course- adjustment knob when

you are on the highest power. You could break the slide or the microscope!

Microscopic things are measured in microns. 1 millimeter = 1000 microns.

In a microscope, the field of view is flipped. If your organism moves up, it will move down in your field of view. If your organism moves left, it will move right in your field of view.

Low Power vs. High Power

Body tube

Revolving Nosepiece

Objective Lenses

Stage Clips

Diaphragm

Light Source

Ocular Lens / Eyepiece

Arm

Stage

Coarse Adjustment

Fine Adjustment

Base

Wrap-Up!Turn to the chapter 2 word wall on page 53.Record at least two “new to you” words that we used in class today.

Aim: How do we determine how big an object is when we look at it under the microscope?

Do Now: Review from yesterday.Figure A represents a cell as viewed by a student using the 10X ocular and the 10X objective of a compound light microscope. Figure B represents the same cell as seen with a different objective. The magnification of the objective used to observe the cell shown in figure B is most likely A. 4X C. 40X B. 60X D. 100X

Notes are in purple.

MagnificationTo determine your magnification…you

just multiply the ocular lens by the objective lens

Example: The ocular is 10x and the objective is 40x, so 10 x 40 = 400

Object is 400 times larger than it is in real life.

How do we determine the size of objects under a microscope?

1. Focus your microscope- make sure that you can see your slide subject!2. Take out a CLEAR ruler with millimeters on it.3. Place the ruler on top of your slide.4. Count how many millimeters there are in your field of view.5. Estimate how big your object is.

Converting from mm to µm

There are 1000 micrometers (µm) in 1 millimeter (mm)State how many µm wide the following objects are.A skin cell is 0.71 millimeters across.A human hair is 1.45 millimeters across.A pollen grain is 0.05 millimeters across.Answers:

710 µm1450 µm50 µm

How big is this object, in µm? Our object

Internet Activity!!http://virtualurchin.stanford.edu/microscope.htm

Wrap-Up!Turn to the chapter 2 word wall on page 53.Record at least two “new to you” words that we used in class today.