Name: ________________________________ Date: ____________ Class: ________________
IB Biology SL (Semester 2)
Drawings, Pictures, and Tables: an Incomplete Exam Study Aid
A note to the student
This study guide will be an extremely useful study tool. Many of the pictures are things that you are required to draw or label. Other
pictures are of things that you need to describe or list. Use it in conjunction with your topics guide and command terms. This is not a
complete or comprehensive guide to the curriculum. However, it is what your teacher thinks are the most important ideas, and images
to help you organize and visualize difficult concepts.
Mitosis and Binary Fission
Mitosis is the process where a eukaryotic cell splits in half to make two identical cells. This is in contrast to prokaryotes, which do
binary fission, a much simpler process. Eukaryotes have to do mitosis because they have many chromosomes, which need to sorted
out so that each daughter cell has the correct number of chromosomes.
Mitosis
Binary Fission
Cell Cycle
The cell cycle of a eukaryote is regulated by several genes. These genes orchestrate the copying of DNA in the S phase, the increase
in size during the G1 and G2 phases, and so on. Mutations to these genes could cause the cell to replicate endlessly, making the cell a
cancer cell.
Meiosis
Meiosis is the process where eukaryotes make sex cells, also known as gametes. These gametes are haploid cells, meaning they have
half of the DNA of the starting cell, called diploid for having a full set of DNA. The steps are similar to mitosis. However, the
differences are important. Notice that in meiosis, crossing over happens during metaphase I and the homologous pairs of
chromosomes separate during anaphase I.
Gene Transfer
This diagram shows how a gene can be taken from one species and placed into another. The organism that has a gene from a different
origin is now called a transgenic organism. This diagram shows how the gene for human insulin can be put into bacteria, which will
then make insulin that can be used for drugs.
Transgenic Organisms
This table is a list of transgenic organisms, which are organisms that have been genetically engineered to have genes from other
species. These transgenic organisms have new traits that are useful to humans, but their creation and use is controversial.
Organism
Use
Rice
Staple crop that contains vitamin A
Corn
A crop that produces proteins that make insects not eat it
Tomato
Salt-resistant crop
Sheep
Livestock that produces human clotting factors in its milk
Pigs
Livestock that contains few antigens, so tissues can be transplanted into humans.
Polymerase Chain Reaction (PCR)
This diagram shows the steps in PCR. In this process, one set of DNA can be copied again and again as many times as desired. These
copies can then be used for other experiments or purposes, such as making a DNA profile. This is how the DNA from one drop of
blood can be copied many times to make DNA fingerprints and conduct other experiments that can be used for criminal justice.
Copying DNA through PCR is also known as amplifying DNA.
DNA Electrophoresis
The diagram and the picture both show how a small sample of DNA (for example, from a crime scene, or by drawing blood from a
person) can be separated in a gel electrophoresis chamber into small fragments of DNA, which are separated by the chamber by size.
This creates a unique pattern called a DNA profile for any person or organism. These DNA profiles are also called “DNA
fingerprints” because they can be used to verify somebody’s identity, just like a fingerprint.
Defense against Infectious Disease
This table outlines differences between viruses and bacteria. The picture shows outside physical barriers to infection, which are many.
Viruses
Size
Structure
DNA?
Surface
Antibiotics





Tiny! (about 0.1µm)
Not a cell
Has DNA or RNA
Has spikes and receptors for infection
Do nothing!
Bacteria





Larger (about 1µm)
Prokaryote cell
DNA in a loop
Has flagella for movement and pili for recognition
Kills them
The Heart: Structures and Pathway of Blood
These two diagrams show the interior and exterior structure of the heart. On the external structures, note the coronary arteries that
supply blood to the heart itself. Having one of these blocked causes a heart attack.
The Transport System
This diagram shows the direction of blood through the heart, as well as the destination of the major blood vessels and arteries. Note
the differences between arteries, veins and capillaries. Arteries must be thicker and more elastic than veins to withstand the high
blood pressure caused by the contractions of the heart. Capillaries must be 1 cell thick, so that diffusion can occur there.
The Ventilation System
These diagrams show the structures of the ventilation system, as well as the comparing inhalation (breathing in) and exhalation
(breathing out). Several muscles flex to accomplish these two different functions. Remember, gas exchange, breathing, and
respiration are three different things. Gas exchange is the diffusion of oxygen and carbon dioxide which takes place in the alveoli.
Respiration, or cellular respiration, is the chemical reactions that create energy for the cell. Breathing is inhalation and expiration, in
which muscles move to create pressure changes that draw air into the lungs, and push air out of the lungs.
Neurons
These two pictures show the structures of a neuron cell, the basic cell that makes up the nervous system. The left picture is an
interneuron, also known as a relay neuron; it connects neurons to other neurons. The right picture is a motor neuron because it
connects to a muscle. The third kind of neuron is a sensory neuron; these have specialized structures for detecting the senses instead
of dendrites.
Action Potential
These three pictures show the process of an action potential. Action potentials are electrical signals caused by the diffusion of sodium
ions into the axon, then the diffusion of potassium ions out of the axon, and then the active pumping of these ions back to their starting
positions. Action potentials travel from the dendrites, through the cell body, and down the axon, ending at the axon terminal.
Synapse
The picture on the left shows the labeled structure of a synapse, the space between two neurons. The synapse is where the electrical
signal (the action potential) becomes a chemical signal. The chemical that carries the signal is called a neurotransmitter. The picture
on the right shows how the drug cocaine effects the synapse. Cocaine is a stimulant, and other drugs that are stimulants also work by
increasing the firing of the receptor on the postsynaptic neuron (the neuron on the bottom of the picture). Drugs called inhibitors do
the opposite: they decrease the firing of the postsynaptic neuron.
Sensory Neurons
This table outlines the 4 basic kinds of sensory neurons.
Name of sensory neuron
What it detects
Examples
Mechanoreceptors
Pressure, texture, vibration
Pain sensors in skin, balance
Chemoreceptors
Chemicals
Taste buds, smell, CO2 concentration in blood
Photoreceptors
Electromagnetic radiation
rods, cones
Thermoreceptors
Temperature
Temperature sensors in skin
Reflex Arc
A reflex arc involves a sensory neuron, interneurons (also known as relay neurons) and motor neurons. Notice how the reflex to react
to pain skips the brain: the signal goes to the spinal cord, and then back to the muscles.
The Eye and the Retina
This picture outlines the structure and function of parts of the eye. The picture on the right zooms in on the retina on the back of the
eye. On it, notice how light passes through ganglion and bipolar cells before reaching the rods and cones, which are stimulated and
then send an action potential off to the optic nerve to be processed in the visual cortex of the brain.
The Ear
This picture outlines the structure and function of parts of the ear.
Regulation of Blood Glucose
This diagram outlines the role of the liver and the pancreas as endocrine organs that regulate blood glucose levels. This is an example
of negative feedback, which keeps the concentration at a balanced, even amount. Diabetes is an endocrine system disorder.
Male and Female Reproductive Systems
These pictures show the structure and function of the male and female reproductive systems.
Menstrual Cycle
This graph shows the levels of the 4 important hormones that regulate the menstrual cycle, and the related events of follicular
development, ovulation, corpus luteum development, and thickness of endometrial lining.
Populations
This concept map shows the factors effecting population size of a species and graphs of the populations resulting from these changes.
Natural Selection
This diagram shows the 4 “steps” of natural selection. In the diagram, the darker colored elk have an advantage, and thus are more
likely to survive; thus, the population changes over time.
Trophic Levels
These two diagrams represent the trophic levels in an ecosystem. Notice the percentages of energy transfer. Unlike nutrient cycles
(such as the carbon cycle), 90% of energy is lost at every trophic level, which is why it has a pyramid shape: every ecosystem will
support a large mass of producers, and a very small mass of apex predators.
Food Web
This diagram is an example of a food web. Arrows point in the direction of energy flow. The numbers listed below each organism is
a the trophic level(s) that that organism is at within the food web.
Carbon Cycle
This diagram illustrates the important processes involved in the carbon cycle. An important component of the carbon cycle is CO2 in
the atmosphere, which is a greenhouse gas.
Human Evolution
These two diagrams show the evolutionary tree of humans, showing where fossil evidence fits in. Notice the timelines, and the
overlapping of several of the taxa. Also, notice the changing dimensions of the skulls.
Classification
Below is the seven levels of hierarchy of taxa of living things. An organism’s scientific name is the Genus and species listed, such as
Tyrannosaurus rex, or Escheria coli. The full classification for Homo sapiens is shown with the hierarchy.
Plant Classification
This table shows 4 phyla of plants and their important characteristics.
4 Phyla of Plants
Animal Classification
This table shows 4 phyla of invertebrate animals (animals without backbones, or vertebrae) and their important characteristics.
6 Phyla of Invertebrates