Study guide
IB BIOLOGY PAPER 1&2 COMPLETE STUDY GUIDE
This is a complete study guide for papers 1 and 2. It contains questions and answers for every syllabus point. It is all I used to study for my final IB exam and I got a 7.
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HOW DID MULTICELLULAR LIFE BEGIN? 1. Aseptate fungal hyphae (Has several nuclei a1. Unicellular organisms attached to each other. continuous cytoplasm and is bigger than average
2. Size and environment increased distance between size.)
cells. 2. Striated muscle cell (Multi nucleated and bigger than
3. Cells were unable to rid of waste and exchange average size.)
products at an adequate rate. 3. Giant algae (Does not follow simple cell structure and
4. Cells differentiated into specialized cells. is much bigger than average size.)
5. Specialized cells are able to perform different life
processes. This is because they have emergent WHAT ARE SOME EXAMPLES OF UNICELLULAR
properties. ORGANISMS?
6. When these fuse together multicellular organisms are 1. Paramecium (heterotrophs in aquatic environments)
formed. 2. Chlamydomonas (autotrophs in soil, fresh water,
oceans, snow mountain tops)
HOW IS TISSUE CREATED?
When a group of specialized cells perform the same HOW DO YOU CALCULATE MAGINIFICATION?
function. 𝑠𝑖𝑧𝑒𝑜𝑓𝑑𝑟𝑎𝑤𝑖𝑛𝑔
𝑀𝑎𝑔𝑖𝑛𝑖𝑓𝑖𝑐𝑎𝑡𝑖𝑜𝑛 =
𝑎𝑐𝑡𝑢𝑎𝑙𝑠𝑖𝑧𝑒
HOW DO GENES WORK IN CELLS? GIVE AN EXAMPLE.
1. Every cell contains all genes but certain genes are
expressed or switched so that it can perform a
particular function.
2. The cells in our nose are called olfactory receptor cells
they express one of the genes to make one type of
receptor to detect one type of odorant so that we can
distinguish smells.
WHAT ARE SOME EXAMPLES OF ATYPICAL CELLS
AND WHAT MAKES THEM ATYPICAL?
1
, Undifferentiated cell from a multicellular organism that can
form more of the same cell indefinitely and differentiate
into specialized cells. E.g. nerve, liver and cardiac.
WHAT DIFFERENT TYPES OF STEM CELLS ARE
THERE?
Totipotent (cells formed following fertilization): Can
become any type of cell
and form complete
organisms.
Pluripotent (embryonic):
Can become a body cell.
Multipotent (umbilical):
WHAT ARE THE FUNCTIONS OF LIFE?
Can become a few closely
Metabolism- chemical reactions including respiration.
related body cells.
Response- reacting to changes in environment.
Unipotent
Sensitivity- reaction to internal and external conditions e.g
Can only become their
warmth and cold
associated cell type.
Growth-an irreversible increase in size.
Reproduction- producing offspring asexually or sexually.
WHAT ARE THE
Excretion-getting rid of the waste products from LIMITATIONS OF EACH SOURCE OF STEM CELLS?
metabolism. Embryos: Higher risk of tumour formation, extraction of
Nutrition- obtaining food to provide energy and the cells causes destruction, if there is no genetic match it could
materials for growth. cause rejection or the need for immunodepressants.
Homeostasis- keeping conditions within the cell at tolerable Umbilical cord blood: Gives rise to limited number of cells.
limits. Adult tissue: Gives rise to limited number of cells. Higher
chance of accumulation of genetic mutations.
WHAT ARE STEM CELLS?
2
,WHAT ARE THE PROS OF EACH SOURCE OF STEM 1. Stem cells from bone marrow, umbilical or peripheral
CELLS? blood are taken by injecting needle and extracting.
Embryos: Easy to extract. Give rise to a lot of cells. 2. Chemotherapy works to kill cancer cells in bone
Umbilical cord blood: Does not have a use, is usually thrown marrow.
away. 3. Stem cells are inserted into the body white and red
Adult tissue: Has genetic match. blood cells are produced in bone marrow.
HOW CAN STEM CELLS BE USED TO TREAT DISEASES?
1. Cell therapy (replacing bad cells with good ones)
2. Transplants
WHAT IS AN ONCOGENE AND WHAT DOES IT DO?
An oncogene is a gene that has the potential to cause
cancer.
HOW CAN STEM CELLS BE USED TO TREAT Proto-oncogenes: proteins that encourage cell division.
STARGARDT’S DISEASE? Tumour suppressor genes: proteins that inhibit cell
Stargardts disease: a disease that is caused when a division.
recessive genetic mutation gene causes the active transport
protein to malfunction and the photoreceptor cells to EXPLAIN THE FORMATION OF TUMORS.
degenerate causing for loss of sight. 1. A mutagen (e.g. UV radiation) causes a mutation.
1. Retinal cells are derived from embryo. 2. This causes the proto-oncogenes to divide rapidly and
2. They are injected into the retina. continue to do so.
3. They become functional. 3. The number of tumour suppressor genes are
outnumbered.
HOW CAN STEM CELLS BE USED TO TREAT 4. Rapid cell division continues forming a tumour.
LUKEIMIA? 5. This then metastasizes into the lymph, blood and
Type of blood cancer caused by high levels of white blood surrounding tissue.
cells. They are at risk of infection.
3
, 1. DNA becomes visible.
2. Chromosomes supercoil and condense to form x
shape.
3. Nuclear membrane disintegrates.
4. Centromeres appear.
5. Centrioles appear.
Metaphase:
1. Spindle fibres from centrioles.
2. Chromosomes line up in the middle of the cell.
Anaphase
DESCRIBE BINARY FISSION. (How prokaryotes 1. Centromere divides allowing the chromatids to
divide)
become separate chromosomes. Sister chromosomes
1. Circular DNA is copied.
are pulled by spindle fibres to opposite sides of the
2. Two DNA loops attach to membrane.
cell.
3. The membrane elongates, pinches and forms two
2. Spindle fibres shorten.
cells.
Telophase
1. Spindle fibres begin to detach.
2. New nuclear membrane and contractile ring starts to
form around sister chromosomes.
DESCRIBE MITOSIS. (How some eukaryotes divide)
DESCRIBE INTERPHASE.
It is the active cell life.
When a cell splits to create two genetically identical
daughter cells.
Prophase:
4
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