Microscopy

TYPES OF MICROSCOPE


Light Microscope
>>Found in most schools
>>Uses compound lenses to magnify objects
>>The lenses bend or refract light to make the object beneath them appear closer

Stereoscope
>>This microscope allows for binocular (two eyes) viewing of larger specimens
>>Usually magnifies 10x to 25x
>>Can be used for thicker specimen
>>Creates a 3D view of specimen

MAGNIFICATION
>>3 types of magnification: Scanning, Low power, High power. Each objective will have written the magnification.
>>In addition to this, the ocular lens (eyepiece) has a magnification.
>>The total magnification is the ocular x the objective.

Scanning - Red ring
Low power - Yellow ring
High power - Blue ring

We can see better details with high power but we cannot see as much as the image.

PRACTICAL: GETTING STARTED ON MICROSCOPE WORK


Question: Does the object appear normal or upside down (under the microscope)?
Answer: Upside down.

Move the slide a tiny bit away from you while observing the object in the microscope.
Question: Does it move away from you or toward you?
Answer: It moves towards me.


Question: Is the field of view larger or smaller when you turn the fine adjustment knob?
Answer: Smaller.


Question: In changing from low power to high power has the position of the image changed?
Answer: Yes, it has.


Here is a picture I took of 3 different coloured threads (blue, green and black) when they were under the microscope.

3 different coloured threads under the microscope

Cell structure and Function

Cell Theory
-All living things are made up of cells.
-Cells are the smallest working units of all living things.
-All cells come from pre-existing cells through cell division


Definition of Cell
A cell is the smallest that is capable of performing life functions.

Two types of cells
-Prokaryotic
-Eukaryotic

Prokaryotic
-Do not have organelles (specialized structures in cells) surrounded by membranes
-Few internal structure
-One-celled organisms e.g. bacteria

Eukaryotic
-Contain organelles surrounded by membranes
-Most living organisms e.g. plant, animal, fungi

SURROUNDING THE CELL


Cell Wall
-Most commonly found in plant cells and bacteria
-Surrounds the cell membrane
-Rigid structure that maintains shape, supports and protects cells
-Permeable to small molecules and small proteins only

INSIDE THE CELL

Cell Membrane

-Selectively/Partially permeable membrane of cell that controls movement of substances in and out of the cell

Nucleus

-Contain chromatins that control cell activities

-Chromatin contain DNA which is the genetic material

-DNA contains instructions for traits and characteristics and to carry out the cell's function

-Separated from cytoplasm by nuclear membrane.

Cytoplasm

-Gel-like mixture

-Surrounded by cell membrane

-Contains organelles

Mitochondria

-Referred to as "powerhouse" of the cell

-The food we eat is transformed into energy (ATP) for the cell and our bodies

Endoplasmic Reticulum

-An interconnected network of tubes and vesicles

-Synthesis of proteins, fats and steroids

-Transports materials around in cell

-Smooth type: lacks ribosomes

-Rough type (in picture): ribosomes embedded in surface

Ribosomes

-Each cell contains thousands

-Make proteins

-Found on endoplasmic reticulum and floating throughout the cell

Golgi Bodies

-Works closely with the ER

-Primary functions is to process and package complex molecules such as proteins and fats that are made by the cell

-Brings there products to the surface of the cell where they can be secreted

-Other secretions include hormones, antibodies, enzymes

Lysosome

-Contain digestive enzymes

-Digest excess or worn-out organelles, food particles and engulf bacteria or viruses

-Also hep repair worn-out plasma membrane

-They also provide sugars, amino acids and bases which are the foundation of macromolecules

-Cell breaks down if lysosome explodes

Vacuoles

-Membrane-bound sacs for storage, digestion, and waste removal

-Central large vacuole - help plant cells maintain shape

-Food vacuoles: formed bu phagocytosis

**Contractile vacuoles (in freshwater protists) : pump excess water out of the cell (Not in syllabus!)

Chloroplast

-Usually found in plant cells

-Contains green chlorophyll

-Where photosynthesis takes place

-Converts light energy into chemical energy in glucose

Difference between Animal cell and Plant cell

-Chloroplast is present in plant cell but absent in animal cell

-Plant cell have a large central vacuole while the animal cell have multiple small vacuole

-Plant cell have cell wall but animal cell no cell wall. Therefore, the plant cell has a fixed shape but the animal cell has an irregular shape.

Harvard VPA 2: A New Frog In Town

Hehe... So I did the second VPA and finally remembered to take screenshots... :D

Jane Goodall, The Chimp Scientist

Dr. Jane Goodall began to observe and study the chimpanzees of Gombe Stream in Tanzania Africa, more than 30 years ago. Back then, people thought that it was not scientific to talk about an animal's mind or personality or to give funny names to their subjects. They also thought of science as experiments that men in white coats conducted in laboratories.

However, science is a particular way of knowing and learning about the world. We can learn the methods of science and put them into practice. Observation and reflection are key aspects of science. Dr. Jane Goodall's field journal documented her observations. She made detailed observations while she kept careful watch on her chimpanzee subjects, using her own abbreviations and note-taking style that were designed to make it easy to write quickly and understand later.

Field notes Jane Goodall took while observing some chimpanzees

It took Goodall close to 4 years to collect a significant amount of information. The chimpanzees were hard to find and resisted her presence for the first couple of years, but eventually came to trust her - this itself was a key observation. She carefully recorded their every move, interaction, gesture, and grunt. She discovered the intricacies of their way of living and social nature and found that chimpanzees are caring, clever and capable of lasting attachments.

Because of Jane Goodall's long term study and observations, we are able to construct our understanding of the true nature of chimpanzees. This is important knowledge because the chimpanzee is the closest living relative of human species. Learning more about them make it possible to learn more about our common evolutionary heritage.

Classification

Why do we classify organisms?
My thoughts: Classifying the organisms helps us to identify the common characteristics between different species.
-Accurately and uniformly names the organisms
-Prevents misnomers such as starfish and jellyfish that aren't really fish
-Use same language (Latin or some Greek) for all names

How many known species are there?

-At least 13 billion! 

-And this is only 5% of all organisms that ever lived!!!

-New organisms are still being found and identified! :)

What is classification?

-Classification is the arrangement of organisms into orderly groups based on their similarities.

-Classification is also known as taxonomy.

-Taxonomists are scientists that identify and name organisms.

Early Taxonomists
-2000 years ago, Aristotle was the first taxonomist.
-Aristotle divided organisms into plants and animals.
-He subdivided them by their habitat

-John Ray, a botanist, was the first to use Latin for meaning
-His names were very long descriptions telling everything about the plant

Carolus Linnaues (16707 - 1778)

-18th century taxonomist

-Classified organisms by their structure

-Developed naming system still used today

-Called the "Father of Taxonomy"

-Developed the modern system of naming known as binomial nomenclature

-Two-word name (Genus and species)

Problems in classifying organisms...
-Species are always changing
-Inter-breeding

Standardized Naming...
-Binomial nomenclature used
-Genus species
-Latin or Greek
-Italicized in print
-CAPITALIZE Genus, but NOT species
-Underline when writing

Rules for Naming Organisms
-The International Code of Binomial Nomenclature contains the rules for naming organisms
-All names must be approved by the International Naming Congresses (International Zoological Congress)
-This prevents duplicated names

Classification Groups
>>Taxon (taxa-plural) is a category into which related organisms are placed
>>There is a hierarchy of groups (taxa) from broadest to most specific
>>Domain, Kingdom, Phylum, Class, Order, Family, Genus, species

Domains
>>Broadest, most inclusive taxon
>>Three domains
>>Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles).
>>Eukarya are more complex and have a nucleus and membrane-bound organelle.


Taxons
Most genera contain a number of similar species, with the exception of Homo that only contains modern humans
Each successive classification category or taxon contains more different types of organisms than the preceding category.

One way to remember the Classification groups... :)
King - Kingdom
Philip - Phylum
Came - Class
Over - Order
For - Family
Gooseberry - Genus
Soup - Species

Observing Primates

Basically, we watched a video of how the gorilla move about and use its arms, legs, hands and feet.

Observation of how the gorilla moves about using their arms, legs, hands and feet.
>>When they are walking, their hands are partially clenched and knuckles are sort of touching the ground.
>>Hunched back
>>Arms are bent at a certain angle

How do they look generally?
>>Arms are longer than their legs
>>Toes look like hands - big toe is very far away from the other 4 toes
>>Walk with limps at times, walk on 4s at times
>>Male gorillas stop moving and pump/hit their chests sometimes

Questions?
>>Doesn't their hands hurt from walking with the partially clenched fist? Why do they walk like that?
>>Why do they walk on 4s at times and 2s at other times?
>>Why do the male gorillas pump/hit their chests? o__O
>>Why such a large difference between the 1st toe and the rest?
>>Do they swing on trees? (lolz..)
>>Why are the arms longer than the legs?
>>Why is their skin so rough/horny?
As we had too many questions, we narrowed them down and chose 2 questions which could be tested.
>>Why do they walk on 4s at times and 2s at other times?
>>Why are the arms longer than the legs?


To clearly understand what sort of questions were testable, we carried out a simple exercise which was found on our worksheet.
>>What is the importance of an opposable thumb for the way in which humans use their hands?
>>Without using your thumbs, can you unpin your nametag from your uniform?


The first question is too general and so we cannot come up with a definite answer. However, the second question is focused on a specific object which is our nametag so it is easier to give an answer for this question than the 1st one.

My 'ahem..ahem...' Drawing

A not very clear drawing of me holding a ruler with my left hand.

Description: Use of 3 fingers (thumb, index finger and middle finger); Thumb is on top; Index and middle fingers are at the bottom - opposite side. :D

Different ways to hold objects

Ways to hold an object...

>> Wrap fingers around the object (fingers meet each other)

>> Using 2 fingers (thumb and index finger) to pick up items

>>Grabbing (using whole palm)

>> Use of three fingers (thumb, index finger and middle finger)

>> 2 palms adjacent to each other (sort of like a scooping motion - hands touching) **(balancing - palms not touching)

>>Using hands and arms (HUGS! <3)

Substance C - Why you no change?

Ok... So this is the substance that I brought home - Substance C

However, over the period of 3 days, it did not seem to show any changes. It did not grow any bigger nor did it become small again. Why is that so? Is it because I did not give it water and it was dry? Is it even possible for it to become small again as it first started out before I put it in water. IS IT A LIVING THING?

Biology 106 Practical 1 - IS IT ALIVE?

On Friday 29th June, we did a practical experiment in the lab. Before we carried out the experiment we recapped on what we knew about living things on Google Docs, here's the link: http://goo.gl/g35sa. For the experiment, we were given 5 unknown substances A, B, C, D and E and were to find out whether they were alive. Here are the steps to the experiment:
1. Label the tube A, B, C, D and E.
2. Carefully transfer 1 spatula full of each of the substance A, B, C, D and E into the respective test tube.
3. Add 3ml of water to each test tube. mix well using the wooden splinter.
4. Start your stopwatch.
5. Observe. Write your observations in table 1. Take readings if you have to.
6. After 10 mins, record the observation again.
7. What is your inference for each of the substance? is there any evidence of life?


Physical appearances of substances A, B, C, D and E:
A: Looks like sand
B: Long, thin particles
C: Circular and transparent
D: Roundish, some brown, some purple
E: Very small dark brown particles


Changes observed after 10 mins:


A: Particles clamp together at the bottom and water becomes murky
B: Substance dissolved in water
C: Substance expanded. Somewhat looks like particles fused together.
D: Little silvery bubble-like "extensions" appear on substance.
E: About half sinks, half floats, a small part of it suspended.


Three different types of liquids - water, glucose and salt water are also provided to test the reactions of the substances to the liquids. Why were these liquids chosen?
This is because glucose is a type of sugar that is an important source of energy to living organisms. Thus, if any of the substances were alive, they may show some sort of reaction after coming into contact with glucose. Water provides dissolved oxygen for the substances if they are alive. As for salt water, if the substance can only survive in salt water, then it would only react to the salt water and not the other two liquids.

An Introduction on MOI

Just a Biology journal of a normal student living in this very complicated world... Have fun reading and  hope it helps a little in ya revision! :)