Science Final Review (December)

Vocabulary (Rounds up all subjects)

1. organism - a living thing
2. unicellular - made of a single cell
3. multicellular - made of many cells
4. metabolism - the combination of chemical reactions through which an organism builds up or breaks down materials
5. stimulus - any change or signal in the environment that can make an organism react in some way
6. response - an action or change in behavior that occurs as a result of a stimulus
7. asexual reproduction - a reproductive process that involves only one parent and produces offspring that are genetically identical to the parent
8. sexual reproduction - a reproductive process that involves two parents that combine their material and produce a new organism which differs from both parents
9. controlled experiment - an experiment in which only one variable is manipulated 
10. autotrophs - an organism that is able to capture energy from sunlight or chemicals and use it to produce its own food
11. heterotrophs - an organism that cannot make its own food and gets food by consuming other living things
12. homeostasis - the condition in which an organism's internal environment is kept stable is spite of changes in the external environment
13. classification - the process of grouping things based on their similarities
14. binomial nomenclature - the classification system in which each organism is given a unique two-part scientific name indicating its genus and species 
15. genus - a classification grouping that consists of a number of closely related similar species
16. species - a group of similar organisms that can mate with each other and produce offspring that can also mate and reproduce
17. prokaryote‌ - a unicellular organism that lacks a nucleus and some other cell structures
18. eukaryote - an organism whose cells contain a nucleus
19. consumers - organisms that eat other organisms to get energy
20. producers - organisms that make their own food through photosynthesis
21. decomposers - organisms that decay organic matter for food and energy
22. cell - basic unit of structure and function in living things 
23. microscope - an instrument that makes small objects look larger
24. cell theory - a widely accepted explanation of the relationship between cells and living things
25. cell wall - a rigid supporting layer that surrounds the cells of plants and some other organisms 
26. cell membrane - a thin, flexible barrier that surrounds the cells of plants and some other organisms
27. nucleus - in cells, a large oval organelle that contains the cell's genetic material in the form of DNA and controls many of the cell's activities
28. organelle - a tiny cell structure that carries out a specific function within the cell
29. ribosomes - a small grain-shaped organelle in the cytoplasm of a cell that produces proteins
30. cytoplasm - the thick fluid region of a cell located inside the cell membrane (in prokaryotes) or between the cell membrane and the nucleus (in eukaryotes)
31. mitochondria - rod-shaped organelles that convert energy in food molecules to energy the cells can use to carry out its functions
32. endoplasmic reticulum - an organelle that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another
33. Golgi apparatus - an organelle in a cell that receives proteins and other newly formed materials from the endoplasmic reticulum, packages them, and distributes them to other parts of the cell
34. vacuole - a sac-like organelle that stores water, food, and other materials 
35. chloroplast - an organelle in the cells of plants and some other organisms that capture energy from sunlight and changes it to an an energy form that cells can use in making food
36. lysosome - a cell organelle which contains chemicals that break down large food particles into smaller ones and that can be used by the rest of the cell
37. tissue - a group of similar cells that perform a specific function
38. organ - a body structure that is composed of different kinds of tissues that work together
39. organ system - a group of organs that work together to perform a major function
40. element - a pure substance that cannot be broken down into other substances by chemical or physical means
41. compound - a substance made out of two or more elements chemically combined in a specific ratio, or proportion
42. carbohydrate - an energy-rich organic compound, such as a sugar or a starch, that is made of the elements carbon, hydrogen and, oxygen
43. lipid - an energy-rich compound, such as a fat, oil, or wax, that is made of carbon, hydrogen, and oxygen
44. protein - large organic molecule made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur
45. enzyme - a type of protein that speeds up a chemical reaction in a living thing
46. nucleic acid - a very large organic molecule made of carbon, oxygen, hydrogen, nitrogen, and phosphorus, that contains the instructions cells need to carry out all the functions of life
47. DNA - deoxyribonucleic acid, the genetic material that carries information about an organism and is passed from parent to offspring
48. mRNA - messenger RNA
49. tRNA - translator RNA
50. rRNA - ribosomal RNA
51. mixture - non-chemical, separable combination of two or more different materials
52. selectively permeable - a property of cell membranes that allow some substances to pass across it, while other cannot
53. passive transport - the movement of dissolved materials across a cell membrane without using cellular energy
54. diffusion - the process by which molecules move from an area of higher concentration to an area of lower concentration
55. osmosis - the diffusion of water molecules across a selectively permeable membrane
56. active transport - the movement of materials across a cell membrane using cellular energy
57. endocytosis - the process by which the cell membrane takes particles into the cell by changing shape and engulfing the particles
58. exocytosis - the process by which the vacuole surrounding particles fuses with the cell membrane, forcing the contents out of the cell
59. cell cycle - the series of events in which a cell grows, prepares for division, and divides to form two daughter cells
60. interphase - the first stage of the cell cycle that takes place before cell division occurs, during which a cell grows and makes a copy of its DNA
61. replication - the process by which a cell makes a copy of the DNA in its nucleus before cell division
62. chromosome - a threadlike structure within a cell's nucleus that contains DNA that is passed from one generation to the next
63. mitosis - the second stage of the cell cycle (after the interphase) during which the cell's nucleus divides into two nuclei and one set of DNA is distributed into each daughter cell
64. cytokinesis - the final stage of the cell cycle (after mitosis), in which the cell's cytoplasm divides, distributing organelles into each of the two new daughter cells

Characteristics of Organisms

• made of cells (unicellular or multicellular)
• have DNA (deoxyribonucleic acid), which is in the cell's nucleus contains the characteristics of an organism
• move (to get water, food, sunlight, or to run from danger)
• reproduce (to prevent the extinction of their species)
• eat (heterotrophs) or make their own food (autotrophs) to get energy
• breathe (oxygen or carbon dioxide)
• grow and develop
• react to stimuli

Needs of Organisms

• food
  • Organisms are divided into three groups, according to how they get their food, these groups are;
    • consumers - eat other organisms to get energy
    • producers - make their food by the process of photosynthesis
    • decomposers - decay organic matter to get energy
• living space (habitat)
  • A living space is the place where organisms live, some examples are;
    • caves
    • soil
    • water
    • inside a tree
• water
  • Water is a basic need because most chemical reactions that take place inside our bodies use water.
  • 70% of the human body is made of water.
• homeostasis
  • All organisms need to live in equilibrium, they need to live a balanced life, for example:
    • balanced sugar levels
    • sweat stabilizes our body temperature
• oxygen or carbon dioxide
• All organisms must breathe oxygen (animals) or carbon dioxide (plants).

Taxonomy

• Taxonomy is a system scientists use to classify organisms.
• Binomial nomenclature was developed by Carolus Linnaeus, it is a two-part name (genus & species) that is given to organisms.
• It is developed in Latin, since Latin is a language that doesn't change

Scientific Method

• The Scientific Method is a series of steps that should be followed to conduct a scientific investigation in the most efficient way possible, it is composed of 8 steps which are;
1. Observe (make observations of everything that surrounds you)
2. State the problem
• The problem must always be stated in the form of a question, for example;
• Will a house plant grow faster if it is given an energy drink on a daily basis?
3. Look up information about the problem (Literary Review)
4. Write the hypothesis (possible answer)
• The hypothesis must always be written in an if, then format, and it must be based on the problem, for example;
• If energy drink is given to a house plant on a daily basis, then it will grow faster.
5. Design and conduct the experiment
• Experiments are conducted to test hypotheses, hypotheses are tested by conducting experiments
6. Collect and analyze data
7. State the conclusion
8. Communicate the results of the investigation
• Variables are the factors that change in an experiment, there are several types of variables, they are;
• Manipulated or Independent Variable - factor changed by the scientist
• Resulting or Dependent Variable - result or outcome from having used the independent variable
• Constant Variable or Control - everything that remains the same, or does not change

• To come to a valid result on an experiment (procedures designed to test hypotheses), control groups and experimental groups are needed on all scientific investigations.
• An experimental group undergoes the independent variable, while the control group remains the same; the purpose of these two groups is to compare the results

Metric System

• The SI, or International System of Units, is French modern adaptation of the metric system, it is the most used metric system in the world. It uses the following units:
• length is measured in meters (m)
• mass is measured in grams (g)
• liquid volume is measured in milliliters (ml)
• distance is measured in meters (m)
• temperature is measured in Celsius degrees (C°)
• Technology has also given us instruments that are used to measure each of these units
• length is measured with a metric ruler
• mass is measured with a beam balance
• liquid volume is measured with a beaker or a graduated cylinder
• distance is measured with a metric ruler
• temperature is measured with a thermometer

Technology

• Technology is the use of knowledge to improve our lives, it is the product of scientific research.
• Science benefits technology and technology benefits science.
• Technology is used in science for medical purposes quite often, for example;
• MRI (magnetic resonance imaging)
• CT scan (computed tomography)
• PET scan (positron emission tomography)
• microscopes
• The SEM (scanning electron microscope) and the TEM (transmission electron microscope) use beams of electrons to produce an image.

Cell Theory

• The first microscope was invented around 1590, this allowed people to see small items
• Robert Hooke, an English scientist, built his own microscopes and made drawings of what he saw
• In 1663 Hooke observed a thin slice of cork, Hooke called the "tiny rectangular rooms" he saw "cells", which means small rooms
• He saw dead cells, but he never knew the importance of what he saw
• Anton van Leeuwenhoek, a Dutch businessman, built microscopes in his spare time
• Around 1674, he became the first person to ever see cells that were alive, he saw them in lake water and called them "animalcules", meaning little animals
• The cell theory is a theory composed of the findings of 3 scientists, it states that;
• All living things are composed of cells
• Cells are the basic units of structure and function in living things
• All cells are produced from other cells
• In 1828, Matthias Schleiden concluded all plants are made of cells.
• In 1829, Theodor Schwann concluded all animals are made of cells.
• In 1855, Rudolf Virchow proposed that new cells are formed from cells that already exist.

Cell Organelles

• Cell membrane - Outer barrier of the cell whose task is to control the movement of substances into and out of the cell. It is also known as a phospholipid membrane.
• Cytoplasm - Substance that supports all of the cell's organelles. It has a network of microtubules and microfilaments.
• Nuclear membrane - Surrounds the nucleus and has pores through which the materials may go in or out of the nucleus.
• Nucleus - Most important cell structure because it controls all of the cell's processes. The nucleus has a cell's genetic code, genetic material (chromosomes and genes). It is the DNA's responsibility to control the cell's activities.
• Nucleolus - Dense area in the nucleus whose task is to make ribosomes.
• ER (endoplasmic reticulum) - Network of tubes that move materials within the cell, There are two types of ER: rough ER and smooth ER. Rough ER has ribosomes attached to it.
• Ribosomes - They are the sites for protein synthesis. Some are attached to the ER, others are on the cytoplasm.
• Mitochondria - Also known as the powerhouse of the cell because of the energy (ATP) produced by a process known as cell respiration.
• Lysosomes - They "digest"and remove the unwanted materials in the cell. Plant cells do not have lysosomes.
• Vacuoles - They have many different tasks such as: enclosing and releasing waste products from the cell. Plant cells have a single large vacuole, animal cells have many smaller ones.
• Golgi Body or Apparatus - It packages and exports substances and complex materials from the cells. Alas, lysosomes are made in the Golgi body.
• Cell wall - Rigid outer boundary that surrounds the cell membrane. It has a strong material called cellulose.
• Chloroplasts - Chlorophyll filled structures where photosynthesis occurs.

Cells' Chemical Compounds

• Elements are found in our body, the smallest unit of an element is called an atom. A single element is made up of a single kind of atom. Some examples of elements are:
• carbon
• hydrogen
• nitrogen
• phosphorus
• sulfur
• Compounds form when two or more elements are combined by a chemical reaction, most elements in living things are in the form of compounds. The smallest unit of a compound is a molecule. A molecule of an compound consists of atoms in place of elements that would be in a compound. Some examples of compounds are water (H2O) and carbon dioxide (CO2)
• Organic compounds are compounds that have carbon
• Inorganic compounds are compounds that do not contain carbon
• Carbohydrates are energy-rich organic compounds made of carbon, hydrogen and oxygen.
• Lipids are organic compounds made of mostly carbon and hydrogen, and some oxygen (fats, oils and waxes).
• Proteins are large organic molecules made of carbon, hydrogen, oxygen, nitrogen and sulfur (sometimes).
• Enzymes are a group of proteins that speed up chemical reactions
• Proteins are made by the following process:
• DNA creates mRNA, rRNA and tRNA
• Coded message given to the mRNA
• Coded message taken to the ribosomes
• Coded message is decoded by the tRNA
• rRNA joins the amino acids and makes the protein

Nucleic acids are very long organic molecules made of carbon, oxygen, hydrogen, nitrogen, and phosphorus.

• DNA is a type of nucleic acid, it carries information about an organism.
• One of the most important components of DNA are the nitrogenous bases, there are four of them, which are joined in the following way:
• Adenosine with Thymine (AT or TA)
• Citosine with Guanine (CG or GC)

Mixtures are separable and non-chemical combinations of different materials. Some examples of mixtures are:

• salad dressing
• fruit salad
• trail mix

Transport in Cells

• Every cell is surrounded by a cell membrane, cell membranes are selectively permeable, meaning it only lets some things pass.
• Substances move into and out of cells by passive transport or active transport.
• Passive Transport is the movement of dissolved materials across a cell membrane without using cellular energy.
• Diffusion is a form of passive transport in which molecules move to an area of higher concentration to an area of lower concentration, it uses no energy from the cell.
• Osmosis is a form of passive transport; it is the diffusion of water molecules across a selectively permeable membrane.
• Facilitated Diffusion is a form of passive transport in which proteins in the cell membrane open pathways through which sugars can pass, this facilitates, or makes easier, the passing of sugars through a selectively permeable membrane.
• Active Transport is the movement of materials across a cell membrane using cellular energy. Proteins in the cell membrane pick up specific molecules and carry them across the cell's membrane; substances that are carried into the cell by this process include calcium, potassium and sodium.
• Endocytosis occurs when large particles want to enter the cell.
• The cell membrane changes shape and engulfs the particle, creating a "food vacuole".
• Exocytosis occurs when large particles want to exit the cell.
• The cell membrane fuses the vacuole, forming an opening to the outside and spilling the vacuole's contents.
• Both of these processes use energy from the cell, therefore, they are forms of active transport.

Cell Cycle

• The Cell Cycle occurs in stages, it includes:
• Interphase - Stage of the Cell Cycle when the cell is not dividing. It is a growth stage of cells in the Cell Cycle.
• Mitosis (cell division)
• Prophase - The nuclear membrane disappears and the chromatin becomes the chromosomes.
• Metaphase - Chromosomes line up along the center of the cell.
• Anapha‌‌se - Spindle fibers form  and attach to the chromosomes.
• Telophase - Spindle fibers pull the chromosomes to opposite sides of the cell.
• Cytokinesis - The cell membrane divides and each new cell is complete. The result is two new cells (daughter cells).
• All cells, except brain neurons, sperms, and ovules undergo mitosis, sperm and ovule cells undergo meiosis.
• A chromosome's "joining piece" is called centromere.
• The goal of this process is to:
• Produce cells for the growth of organisms
• Repair dead, injured or old cells
• Reproduction

NOTE: This is just a review, it is highly recommendable you read your notes and the book chapters that are coming.