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Chapter 2-1
• chemical compound: one or two elements joined chemically in a
specific ratio
• organic compound: compounds found in living things
Proteins
- made of carbon, oxygen, hydrogen, nitrogen, and some of them also
of sulfur
- for build up and repair of tissues
- found in foods such as meat, eggs, beans, nuts
- made up of amino acids (20) in different numbers and arrangements
(order and kind)
- enzymes are proteins that help processes like digestion
Carbohydrates
- made of carbon, oxygen, and hydrogen
- give energy
- found in foods as starch (complex carbohydrate) in potato or rice and
as glucose (simple carbohydrate) in fruits; cellulose in plants is
another complex carbohydrate.
Lipids (fats, oils, waxes such as cholesterol)
- made of carbon, oxygen, and hydrogen
- give stored energy but more energy gram for gram than carbohydrates
- found in foods such as oil, butter, meat, cheese
Nucleic Acids
- made of carbon, oxygen, hydrogen, nitrogen, phosphorus
- 2 types: DNA (genetic material) and RNA (helps in protein
synthesis)
• inorganic compound: doesn’t come from living things
Water is used for
- carrying substances in the body
- controlling body temperature
- keeping the size/shape of cells
- helping processes like digestion
Chapter 2-2
• The cell membrane is a selectively permeable membrane. It lets
needed materials like nutrients, water, and oxygen in and it lets wastes
like carbon dioxide out. Some large molecules and salts don’t pass.
• There are 2 ways by which materials can pass through the cell
membrane:
1. Passive Transport
a. diffusion: particles move from a place with more concentration to
a place with less concentration. Ex. Nutrients, oxygen, wastes
b. osmosis: is the diffusion of water only. Ex. Within the blood cell
(check the pictures in the book)
2. Active Transport
Particles move from a place with less concentration to a place with
more concentration. Ex. The passage of some minerals in plant cells,
amoeba engulfing food
• Cells are very small, therefore it is easier to bring materials in and out.
Chapter 2-3
Photosynthesis is the process of capturing sunlight to make food and oxygen
in plants (photo means light and synthesis means to make).
• Stage 1: sun’s energy is captured by the chlorophyll in the
chloroplasts of the leaves. Chlorophyll contains pigments which
absorb light and also make the organism green. The green color
masks all other colors in the organism except in fall when leaves turn
brown, red, orange, and yellow.
• Stage 2: the captured energy is used to make glucose used as energy
and also to make oxygen which is given out to the air to be used by
animals for respiration. To complete the process of food making, in
addition to the energy plants also need carbon dioxide entering from
the air (given out by animals) through the stomata on the leaves as
well as water entering from the soil through the roots.
Know the chemical equation for the process of photosynthesis.
Yield
Reactants
(Staring materials)
Products
(End Results)
Chapter 2-4
Respiration is the process by which food (glucose) is broken down to give
energy.
• Stage 1: occurs in the cytoplasm where glucose breaks down into
smaller molecules. Only a small amount of energy is made.
• Stage 2: occurs in the mitochondria where glucose breaks down with
the help of oxygen. A lot of energy is made.
Breathing is different from respiration in that it is the act of bringing oxygen
in and letting carbon dioxide out.
Know the chemical equation of respiration.
Photosynthesis and respiration are opposite reactions: the reactants of one
are the products of another and the products of one are the reactants of
another.
Fermentation is when glucose is broken down without oxygen. It produces
less energy than respiration.
• Alcoholic fermentation: occurs in yeast producing energy, carbon
dioxide, and alcohol. The carbon dioxide is used by bakers to make
dough rise and the alcohol is used to make beer.
• Lactic Acid fermentation: occurs in muscle cells producing energy,
carbon dioxide, and lactic acid. The lactic acid causes the soreness
that you feel after doing strenuous exercise, especially when you
haven’t exercised for long periods of time.
Chapter 2-5
• Cell growth means more cells and bigger size.
• Cell cycle involves all the processes of growth and cell division. It is
divided into the Interphase, Mitosis, and Cytokinesis parts. The cell
that is dividing is the parent cell and the resulting cells are known as
daughter cells.
• Interphase: occurs before cell division; cell is still active
- growth: the cell doubles its size and produces all needed
structures
- DNA replication: DNA makes its own copy so that each
daughter cell gets the same information to survive
- the cell prepares to divide
• Mitosis: the nucleus divides resulting in 2 nuclei each getting a copy
of DNA
- Phase 1: Prophase
a. chromatin condenses to form rod-like chromosomes; each
chromosome is made up of 2 chromatids attached at the
centromere
b. spindle fiber between ends of the cell forms
c. nuclear membrane breaks
- Phase 2: Metaphase
a. chromosomes line up on the spindle fiber in the middle held
by their centromeres
- Phase 3: Anaphase
a. centromeres split; chromatids separate
b. each chromatid of the pair moves to opposite ends of the cell
c. cell is stretched
- Phase 4: Telophase
a. chromosomes stretch and become coiled again
b. a new nuclear membrane forms around each set
• Cytokinesis: is the division of the cytoplasm which results in the cell
dividing into 2 identical cells, meaning they have the same number of
chromosomes as the parent cell
Animal cells, Plant cells, and Yeast cells divide differently.
• The length of the cell cycle depends on the type of the cell and the
type of the organism.
• Structure of the DNA:
- double helix
- made up of the sugar Deoxyribose and phosphate groups on the
sides and Nitrogen bases (Adenine, Thymine, Cytosine, and
Guanine) on the rungs in the middle.
- Replication of DNA
a. the 2 sides of the DNA unzip and separate
b. free floating Nitrogen bases in the nucleus come and pair
with each matching base on both sides of DNA
c. 2 new DNA molecules are formed exactly identical to each
other and the parent DNA