Biology

Biology living/once-

living things

What determines if something is living?

“the study of”

There is no single definition of life. However, there is a list of characteristics by which we determine if something is living or not.

In order to be considered “living”, you need to display the potential for all of the following life functions:1. Nutrition-obtaining materials from the

environment and processing them for use within the organism.

a. heterotrophs-organisms that consume food (dog, human)

ingestion- digestion-

egestion-

taking in foodbreaking down foodremoval of undigested or indigestible food ex) corn, fiber, throwing up

What must an oak tree do to stay alive that both a fly and a human must also do?

b. Autotrophs-

*Photosynthesis:

“auto”= self

“trophic”= nutrition (plants)

chlorophyll

light

enzymes

CO2 + H2O C6H12O6 + O2 + H2O

2. Transport- the absorption and circulation of materials within an organism

•a. single-celled organisms (or any cell w/in an organism…

materials are diffused/absorbed directly across the cell membrane •b. multi-celled organisms- most cells aren’t in contact w/the environment so a circulatory system is needed

•a. anaerobic-

3. Respiration-The exchange of O2 and CO2 AND the release of energy that is stored in food molecules.(glucose)

does not use oxygen, produces little energy•b. aerobic- does use oxygen, produces lots of energy, more efficient C6H12O6 + O2 CO2 + H2O + Energy (36 ATP) (glucose)

4. Excretion-

The incorporation of these synthesized molecules into the organism’s bodyEx) when proteins become part of a body builder’s muscles from a protein-rich diet

•skin removes H2O, salts + urea

•lungs remove CO2 + H2O

•kidneys remove H2O, salts + urea•liver removes dead RBCs

5. Synthesis & Assimilation-

chemical reactions where large molecules are built from smaller ones

the removal of wastes from cells + from an organism which were produced during life processes.

“You are what you eat!!!”

6. Regulation-the control & coordination of all life activities in an effort to maintain homeostasis(stable internal

enviroment)•a. nervous- •b. endocrine-

2 systems involved:electrical: brain, spinal cord, nerves chemical: hormones, glands

7. Growth-increase in size and/or number of cells• you grow in # of cells from infant teen• an ameba’s 1 cell can increase in size• requires materials that were synthesized from the nutrients ingested

8. Reproduction-creating a new organism/cell

~species survival is dependent on reproduction, individual survival is not.

•2 parents,•offspring have a combination of parents’ traits

•1 parent,•identical offspring,•no variety

~asexual & sexual

Metabolismthe total of all life processes/chemical

reactions working together to keep an organism alive

Homeostasis

The maintenance of a stable internal environment w/in an organism

ex) maintaining a constant body temperature, blood sugar level

Borderline cases of living things:Seeds, flower bulbs, viruses, HIV

They display only some of the life functions some of the time. At other times, they are said to be dormant (“sleeping”)

More on viruses……..•contain genetic material but lack other cell

structures to carry out metabolism•they are not cells and do not fit into any kingdom•they cannot reproduce without a host cell

…….disruption of homeostasis!!

http://phschool.com/Enter code cbp-6192

End of notes for Life Function Quiz

How did we discover the cell?

The Cell`the basic unit of all living things

Historical Background (don’t need to put in notes)

2. Anton Von Leeuenhoek- used a simple microscope (1 lens). He was the

1st to see living cells (blood, pond water

organisms)

1. Robert Hooke- coined the word “cell” when

looking at cork w/a compound microscope (he was seeing their cell walls)

A. 1600s

3. Schleiden (1838)- said that all plants are made of cells

2. Brown- (1831) 1st to see a nucleus

B. 1800s1. Dutrochet- (1824) stated that all living

things are made of cells

4. Schwann (1839)- said that all animals are made of

cells4. Virchow (1855)- said that all cells arise from other

cells

3. New cells arise from other cells.

2. Cells are the basic unit of structure and function

(can carry out life processes).

1. All living things are made of 1 or more cells.

Laser clip “Intro to Cell Study”

~where did the 1st cell come from?Exceptions to the Cell Theory

~viruses: not made of cells, no DNA, can only reproduce w/host cell

These discoveries led to the development of the Cell Theory

•1 lens

Microscopes

•magnifies 40-400 times•2 lenses

•AKA magnifying glass•magnifies 3-10 times

1. Simple-

2. Compound- (what we use at school)

•See diagram

body tube

nosepiece

objective lens

objective lensobjective lensstage clips

diaphragm

light

ocular/eyepiece

arm

stage

coarse adjustmentfine adjustment

base

Practice w/this diagram:

3. dissecting/stereo microscope-

4. Electron-

•2 eyepieces: binocular•magnifies 6-60 times•shows external features (ex. fly, ladybug)•creates a 3-D image

•developed in 1930s•bounces electrons off of specimen (instead of light)

•views specimens in a vacuum (kills live specimens)

•magnifies more than 250,000 times•creates a 3-D image

Tips for microscope use:•Start on low power

•Brighter•Larger field of view

•When you switch from low to high:•center your specimen, b/c you will only see a fraction of the center of the specimen when you go to high power •the field of view gets smaller and darker•only use fine adjustment on high power•objects appear upside down and backwards in the field becom

es

under the scope

•To get total magnification:multiply the power of the eyepiece by

objective lens

•when you move the slide to the left, the image moves to the right & vice-versa

Preparing a wet mount slide:•add a drop of water to a slide

•add specimen (cheek cell, onion cell, etc.)•put coverslip on at a 45o angle (removes air bubbles)

•Place 1 drop of stain at the edge of the coverslip•Place a paper towel at the opposite edge so that the water from under the coverslip is absorbed and stain is drawn under coverslip

Staining a specimen:

paper towel

stain

How do you measure organisms under the microscope???

You can use ruler under low power:

Microscopic Measurement:

in a meter, there are 1000mm (millimeters) in 1 mm., there are 1000 um (micrometers/microns)

Determine the approximate

diameter of the cell in um.

1.6 mm. (diameter of the field of view)

The cell takes up approxone quarter of the field

1.6 / 4 = .4 mm. = 400um

Units:

Chromatography- “chrom” = color process in which a substance (ink,

chlorophyll) is separated into its component parts/colors By comparing the separation color bands of the unknown substances to that of a known substance, an identification may be made.

When heating a material in a test tube: Always wear goggles when using chemicals.

never put a stopper in the tube point tube away from you

glassware:

Misc Lab Tips….

beaker test tube

flasks

Graduated cylinder-

always read volume at meniscus

Science uses the metric system:

gramslitersmeters

with prefixes such as milli-centi-kilo-

Conducting an Experiment:A valid experiment must have the following elements: A question you are trying to answer or problem you want to investigate

A control- the setup that remains the same through the experiment; provides a comparison

A variable-the element/factor that changes in the experiment (amount of sun, water)

-a valid experiment tests only ONE variable at a time

variable that does not depend on a factor in the experiment (ex. time, days)

relies on the independent variableex) plant growth depends on time, time does not depend on plant growth

independent-

dependent-

A hypothesis-possible answer to the question you are asking often posed as an “if…then…” statement

Data-

what you see happening; provides data for analysis

A conclusion-Sums up the findings. Scientists use the data to determine whether the hypothesis was supported or refuted

Sample size-Refers to the # of organisms being tested. The larger the sample size, the more valid the results are.

An observation-

must be measureable (height, length, number)

# of trials- the more trials you do, the more valid your experiment is

The Cell

organelle

Present in all living things Have many tiny “organs” called

organelles These organelles carry out life functions Cells can be organized into more complex levels:

cell

tissue

organ

organ system

organism

Smallest unit of living things

Cell size & scale illustration

Cells are specialized to perform different functions ex)nerve cells carry electrical messages muscle cells move body parts

gland cells produce hormones Cells are most often microscopic (10- 100 um)

exceptions:chicken egg- 6 cm.nerve cell- up to 1 meter!

Cell Organelles small structures inside cell suspended in cytoplasm (the watery

material inside the cell where chemical reactions

occur) carry out life functions

1. Cell (plasma) membrane-

Surrounds and protects the cell is selectively permeable (regulates

the passage of materials into and out of the cell) and

therefore maintains homeostasis (tries to) Recognizes chemical signals from outside

the membrane or from other cells using:

*Life function: Transport, Regulation, Excretion

receptors- structures on the membrane that receive outside “messages” (have specific shapes and will only allow things inside the cell that fit their shape!)

cell

receptors“message”

Receptors:

Video clip: membrane

Virus receptor clip,http://phschool.com use code cbp 6192

control center for the cell (brain)

contains:

2. nucleus-

chromosomes-(DNA in rod-like, coiled form)

*Life function: regulation, reproduction, metabolism, etc

synthesize proteins may be free in cytoplasm or lining E.R.

a network of fluid filled channels connected to the nuclear membrane

transport materials w/in cell

*Life function: synthesis

3. ribosomes-

4. Endoplasmic Reticulum- (“ER”)

smooth ER- not lined w/ ribosomes rough ER- lined w/ribosomes

*Life function: transport, synthesis

5. lysosomes-“stomach” of the cell

small sacs that contain digestive chemicals*Life function: nutrition

6. vacuole- membrane enclosed sacs

~food: contain food & fuse w/vesicle~ contractile: in freshwater protists,

pumps out excess water

plant vacuoles are much larger than animal

site of cellular respiration; releases energy (ATP)

(powerhouse)

*Life function: nutrition, excretion, homeostasis7. mitochondria-

*Life function: respiration

8. chloroplasts-found in plant cells onlycontain chlorophyll• site of photosynthesis

*Life function: synthesis, nutrition

12. Cell wall-

non-living

composed of cellulose (complex carbohydrate)

surrounds & supports plant cells

13. Cilia & flagella- hair-like structures that help an organism

move ciliaflagella

*reminder………

A cell can be part of a multicellular organisn (dog, tree)

OR

A cell can be an entire organism (ameba, paramecium)

HOW?!• the organelles present in a single

celled organism act like the systems (resp., excretory, etc) in a multicellular organism

• these organisms perform all of the life functions needed to stay alive

“cyto” =

Large vacuolesChloroplastsCell membrane & cell wall

Small vacuolesNo chloroplastsCell membrane only

*reminder………

prefix meaning cell

Laser clip: cell

*review life funct

plant cells animal cells