Study Guide for Chapters 2 and 3 - Pages 38-79
1. Cell – Basic unit of life. Smallest functional and structural unit of all organism.
2. Six Characteristics of living things.
1. Have cell
2. Sense and respond to change – stimulus and response
3. Reproduce
4. Have DNA
5. Use energy
6. Grow and develop
3. Stimulus – Anything that causes a reaction or change in an organism or any part of an organism.
Example: Alarm clock is the stimulus for you to get up in the mornings.
4. Homeostasis- The maintenance of a constant internal state in a changing environment…Your
body maintains stable internal conditions such as your body temperature.
5. Sexual reproduction – two parent produce offspring that share characteristics of both parent.
Offspring are genetically unique.
6. Asexual reproduction – One parent produces offspring that are genetically identical to the
parent. Hydras reproduce by asexual reproduction, budding. See page 40. Bacteria reproduce
asexually by binary fission.
7. Four needs of living things.
1. Water
2. Air
3. Place to live
4. Food
8. Importance of water. Cells are 70% water. Water is needed for the chemical reactions in cells.
9. Proteins – Molecules made up of amino acids. They are needed to build and repair body
structures and to regulate processes in the body.
10. Carbohydrates – Molecules that include sugars, starches, and fiber. There are simple
carbohydrates like sugar and complex carbohydrates like starch.
11. Lipids– Fat molecules that store energy.
12. Phospholipids – Molecules that form most of the cell membrane.
13. ATP – Adenosine triphosphate – a molecule that acts as the main energy source for cell
processes.
14. Nucleic acids – Molecules made of nucleotides. Example- DNA
15. Robert Hooke – He was the first person to describe cells. He looked at a piece of cork through
the microscope he made and maned the “boxes” he saw….cells.
16. Microscope history – Cells were not discovered until microscopes were invented in the 1600’s.
Robert Hooke and Anton van Leeuwenhoek made their own microscopes.
17. Cell theory –
1. All organisms are made of one or more cells.
2. The cell is the basic unit of all living things.
3. All cells come from existing cells.
18. Why are cells so small? Cells are small so that they can take in nutrients quickly and remove
wastes quickly. This helps the cell survive. Cells are small because their size is limited by their
surface area-to-volume ratio. Because of homeostasis the correct ratio is maintained. This
allows cells to take in nutrients and remove wastes quickly and to survive.
19. Cell membrane – A phospholipid layer that covers a cell’s surface and acts as a barrier between
the inside of a cell and the cell’s environment. It controls materials going in and out of the cell.
All cells have a cell membrane.
20. Cytoplasm – the fluid inside of the cell which contains or holds the organelles.
21. Organelles – The small bodies in a cell’s cytoplasm that has a specific job or function in the cell.
22. Nucleus – Found in eukaryotic cells. It is the organelle that contains the DNA and that has a role
in processes such as growth, metabolism, and reproduction.
23. Prokaryote – An organism that does not have a nucleus. Example: Bacteria and archaea…the
genetic material floats in the cytoplasm.
24. Eukaryote – An organism whose cells have a nucleus. Examples: Us/animals and plants.
25. Archaea – Prokaryotes that live in places where no other organisms could live. They live in
extreme heat and in extremely salty waters.
26. Multicellular – many cells.
27. Unicellular – single celled
28. Autotrophs – organisms such as plants and algae that produce their own food through
photosynthesis.
29. Heterotrophs – organisms that eat other organisms to get their food….like us.
30. Cell wall – a rigid structure that surrounds the cell membrane and provides support to the cell.
Plant cells, fungal cells, and bacterial cells have a cell wall.
31. Cytoskeleton – a web of proteins in the cytoplasm which keeps the cell’s membrane from
collapsing. It helps a cell keep its shape.
32. Nucleolus – the round structure in the nucleus which makes the ribosomes.
33. Ribosomes – organelles that make the proteins. They are the smallest of all organelles. All cells
have ribosomes.
34. Endoplasmic reticulum – It is part of the internal delivery system of the cell. It is a system of
membranes that help in the processing and transport of proteins. The smooth ER produces
lipids. The rough ER has ribosomes on it and the smooth ER does not.
35. Mitochondrion or mitochondria – The power source of the cell. It produces energy/ATP. Most
of a cell’s ATP is made and stored in the inner membrane of the mitochondrion. It is the cell
organelle where cellular respiration takes place.
36. Cellular respiration – the process by which organisms use glucose and oxygen to produce carbon
dioxide, water, and ENERGY/ATP. This takes place in the mitochondria.
37. Chloroplasts – the organelles that use the energy of the sunlight to make food through the
process of photosynthesis. They are green because they contain the pigment chlorophyll which
captures the light energy so that photosynthesis can take place.
38. Photosynthesis – the process by which producers (plants and phytoplankton/algae) use sunlight,
carbon dioxide, and water to produce glucose and oxygen.
39. Golgi complex – the cell organelle that packages and distributes proteins and other materials
into and out of the cell.
40. Vesicles – small sacs that surround materials to be moved into or out of a cell. They carry
materials between organelles such as the endoplasmic reticulum and the Golgi complex.
41. Lysosomes – organelles that digest food particles, wastes, and worn out cell parts.
42. Vacuole – an organelle that aids/helps in the breakdown of wastes in plant cells the way
lysosomes do in animal cells. The large central vacuole in plant cells stores water and other
materials.
43. Four levels of organization.
1. Cells
2. Tissues
3. Organs
4. Organ systems
Note: the levels move from simplest to most complex.
44. Tissue – a group of similar cells that perform a common function.
45. Organ – a collection of tissues that carry out a specialized function of the body.
46. Organ system – a group of organs that work together perform body functions.
47. Structure – the arrangement of parts in an organism.
48. Function – the special activity of an organ or part.
49. How can you tell if a cell is a bacterial cell, a plant cell, or an animal cell? Bacterial cells have no
nucleus. They do have a flagellum, cell wall, cell membrane, cytoplasm, ribosomes, and genetic
material/DNA. Plant cells and animal cells have a nucleus. The difference is that plant cells have
a cell wall, chloroplasts, and a large central vacuole. Animal cells have lysosomes. Both plant
and animal cells have mitochondria, the endoplasmic reticulum, the Golgi complex, a cell
membrane, ribosomes, cytoplasm, and a cytoskeleton.