Ib Biology Notes

Biology
IB Standard Level
2012-2014

Index

Topic 1

Topic 2

Topic 3

Topic 4

Topic 5

Topic 6

Topic 7

Topic 8

Topic 9

Topic 10

Topic 11 Statistical analysis

Cells

The chemistry of life

Genetics

Ecology and evolution

Human health and physiology

Nucleic acids and proteins

Cell respiration and photosynthesis

Plant science

Genetics

Human health and physiology

Topic 2- Cells

1. Cell theory
a. Outline the cell theory
b. Discuss the evidence for the cell theory
c. State that unicellular organisms carry out all the functions of life
d. Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells using the appropriate Sl unit
e. Calculate the linear magnification of drawings and the actual size of specimens in images of known magnification
f. Explain the importance of the surface area to volume ration as a factor limiting cell size
g. State the multicellular organisms show emergent properties
h. Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others.
i. State that stem cells retain the capacity to divide and have the ability to differentiate along different pathways.
j. Outline one therapeutic use of stem cells.

2. Prokaryotic cells

a. Draw and label a diagram of the ultrastructure of Escherichia coli (E. coli) as an example of a prokaryote
b. Annotate the diagram from (2a) with the functions of each names structure.
c. Identify structured from (2b) in electron micrographs of E. coli

3. Eukaryotic cells

a. Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell
b. Annotate the diagram from 3a with the functions of each names structure
c. Identify structures from 3a in electron micrographs of liver cells
d. Compare prokaryotic and eukaryotic cells
e. State three differences between plant and animal cells
f. Outline roles of extracellular components.

4. Membranes

a. Draw and label a diagram to show the structure of membranes
b. Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes
c. List the functions of membrane proteins
d. Define diffusion and osmosis
e. Explain passive transport across membranes by simple diffusion and facilitated diffusion
f. Explain the role of protein pumps and ATP in active transport across membranes
g. Explain how vesicles are used to transport materials within a cell between the rough endoplasmic reticulum, Golgi apparatus and plasma membrane.

5. Cell division

The essential Processes
Characteristic of Living Things

Transfer of energy metabolism
Growth & Development Reproduction
Movement & Locomotion Excretion
Responsiveness& Sensitivity Homeostasis
Feeding & Nutrition Adaptation

Glossary

Pili

Topic 2.2

Prokaryotic organisms vs. eukaryotic organisms

Prokaryotic organisms:

Cell type: nucleoid. smaller in size (5-10) micrometer). Fewer organelles.

Prokaryotic cells do not make up unicellular organisms.

Eukaryotic organisms:

Cell type: True nucleus. Larger in size, 200 micrometer. More organelles

Introduction to Bacteria

What are bacteria?

Bacteria are single celled organisms (unicellular), they are very small and can be found pretty much everywhere. E.Coli helps us digest food but can also make you sick. They are found in three basic shapes:

Rod-shaped called bacilli
Rod shaped bacteria that divide only across their short axis. Most occur as single rods, although pairs and chains are also found. The term bacillus can refer to shape. It may also denote a genus.
Round shaped called cocci
Usually round, but sometimes oval or elongated. When they divide, the cells stay attached to each other and remain in aggregated eg. pairs (diplococci) or (staphylococci), that are usually a feature of the genus.
Spiral shaped and vibrio
Bacteria with one or more twist. Spirilla bacteria have a helical (corkscrew) shape which may be rigid or flexible (as in spirochetes). Bacteria that look like curved rods (comma shaped) are called vibrios.

Some are single, while others cluster together. Bacteria reproduce in numbers, not size through binary fission (asexually). Binary fission created genetically identical offspring. It's a replication of DNA, DNA move to different parts of bacterial cell. Then cell divides. This does not transfer genetic material.

Bacteria also reproduce through conjugation, bacterial equivalent of "sexual" reproduction. Conjugation transfer genetic material but do not reproduce. The two bacteria illustrated below are involved in "pseudo sex". This involves a one-way exchange of genetic information from a donor cell to a recipient cell. The plasmid which must be of the "conjugative" type, passes through a tube called a sex pilus to the other cell. Which is donor and which is recipient appears to be genetically determined.

How do bacteria eat?

Some make their own food from sunlight, like plants. These are called Photosynthetic bacteria and are autotroph (create their own food). Others are scavengers, they share the environment around them, while others are warriors, they attack other living things. These two are heterotrophs.

Some bacteria are Pathogens, these make you sick. They get food they need to survive and reproduce and produce toxins that result in fever, headache, vomiting, and diarrhea and destroy body tissue. Some common pathogens are

Pathogenic E. coli
Found in ground beef, contaminated fruits and vegetables
Salmonella
Found in raw meats, poultry, eggs, sprouts, fruit and vegetables
Listeria
Found in deli foods, lunch meats, smoked fish and vegetables

Not all bacteria are harmless and some are helpful, like

Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in you intestine. can be found in human intestines and mouth to improve digestion.
Leuconostoc: makes pickles & sauerkraut.
Pediococcus: Used in production of fermented meats.