Summary of biology compulsory 1 of PEP Review the key points, difficulties, and test points

Summary of biology compulsory 1 of PEP Review the key points, difficulties, and test points

Biology compulsory 1 review outline (Compulsory)
Chapter 2 chemical composition of cells
Section 1 atoms and molecules in cells
1、 The atoms and molecules that make up a cell
1. C, h, O, N, P and Ca were the most abundant elements (98%)
2. The basic element of organism: element C. (carbon chain formed by covalent bond between carbon atoms is the basic skeleton of biological macromolecules, which is called the carbon skeleton of organic matter.)
3. Lack of essential elements may lead to diseases, such as Keshan disease (selenium deficiency)
4. The unity and difference between biological and abiotic world
Unity: the chemical elements of organisms can be found in inorganic nature, and none of them is unique to the biological world
Difference: the content of chemical elements in organism is quite different from that in nature
2、 Inorganic compounds in cells: water and inorganic salts
1. Water: (1) content: 60% - 90% of the total cell weight. It is the most abundant substance in living cells
(2) Form: free water, combined water
 free water: free water, which exists in free form and can flow freely. Its functions include: ① good solvent; ② participating in intracellular biochemical reaction; ③ material transportation; ④ maintaining cell morphology; ⑤ thermoregulation
(in cells with high metabolism, the content of free water is generally high.)
&#Binding water: water combined with other substances. Its function is an important component of cell structure
(the increase of combined water content can enhance the stress resistance of plants.)
2. Inorganic salt
(1) Form of existence: ion
(2) Function
① It combines with proteins and other substances to form complex compounds
For example, Mg 2 + is the component of chlorophyll, Fe 2 + is the component of hemoglobin, and I - is the component of thyroid hormone
② Participate in various life activities of cells (such as muscle twitch when calcium concentration is too low, muscle fatigue when calcium concentration is too high)
Section 2 biological macromolecules in cells
1、 Sugars
1. Element composition: C, h, O three elements
2. Classification
Main functions of concept type distribution
The substance that makes up nucleic acid in animal and plant cells
Deoxyribose
Glucose is an important energy source for cells
Sucrose plant cells that can produce two molecule monosaccharide after hydrolysis of disaccharide
malt dust
Lactose animal cells
After the hydrolysis of polysaccharides, many monosaccharide molecules can be produced, which are the energy storage substances in plant cells
The basic components of cellulose plant cell wall
Glycogen is an energy storage substance in animal cells
The hydrolysates of disaccharide and polysaccharide are as follows
Sucrose → 1 glucose + 1 fructose
Maltose → 2-glucose
Lactose → 1 glucose + 1 galactose
Starch → maltose → glucose
Cellulose → cellobiose → glucose
Glycogen → glucose
3. Function: carbohydrate is the main energy source of life support
(in addition, it can participate in cell recognition, intercellular material transport, immune function regulation and other life activities.)
4. Identification of sugar
(1) Starch turns blue when it meets iodine solution, which is a special color reaction of starch
(2) Reducing sugars (monosaccharide, maltose and lactose) and Fehling's reagent can form brick red precipitate under the condition of water insulation and heating
Feilin reagent: preparation: 0.1g/ml NaOH solution (2ml) + 0.05g/ml CuSO4 solution (4-5 drops)
Use: use after mixing, and use now
2、 Lipids
1. Element composition: mainly composed of C, h, O (C / H ratio is higher than sugar), some also contain n, P
2. Classification: fat, lipids (such as phospholipids), sterols (such as cholesterol, sex hormones, vitamin D, etc.)
3. Function:
Fat: the main storage form of energy required for cell metabolism
Phospholipid in lipid: it is an important material to form biofilm
Sterols: play an important role in cell nutrition, regulation and metabolism
4. Identification of fat: fat can be dyed orange by Sudan III dye
(in the experiment, wash off the floating color with 50% alcohol → observe under microscope → orange fat particles)
3、 Protein
1. Elemental composition: in addition to C, h, O, N, most proteins also contain s
2. Basic composition unit: amino acids (about 20 kinds of amino acids make up protein)
General formula of amino acid structure:
The judgment of amino acid: ① there are amino and carboxyl groups at the same time
② At least one amino group and one carboxyl group are attached to the same carbon atom
(the difference of 20 amino acids in protein: the difference of R group)
3. Formation: many amino acids are dehydrated and condensed to form peptide bonds (- CO-NH -) to form peptide chains, and many peptide chains curl and fold to form functional proteins
Dipeptide: a peptide chain consisting of two amino acid molecules
Polypeptide: a peptide chain consisting of n (n ≥ 3) amino acid molecules linked by peptide bonds
The reasons for the diversity of protein structure are as follows: the type, number and order of amino acids that make up the polypeptide chain of protein are different;
The number and spatial structure of polypeptide chains are different
4. Calculation:
The number of peptide bonds in a protein molecule (the number of water molecules removed) = the number of amino acids - the number of peptide chains
The number of amino groups (or carboxyl groups) in a protein molecule is at least equal to the number of peptide chains
5. Function: the main undertaker of life activities
6. Protein identification: purple color reaction with biuret reagent
Biuret reagent: preparation: 0.1g/ml NaOH solution (2ml) and 0.01g/ml CuSO4 solution (3-4 drops)
Use: separate use, first add NaOH solution, then add CuSO4 solution
4、 Nucleic acid
1. Element composition: C, h, O, N and P
2. Basic unit: nucleotide (composed of 1 molecule phosphate + 1 molecule pentose + 1 molecule nitrogenous base)
1 molecule phosphoric acid
Deoxynucleotide 1 molecule deoxyribose
(4) 1 molecule nitrogenous base (a, t, G, c)
1 molecule phosphoric acid
Ribonucleotide 1 molecular ribose
(4) 1 molecule nitrogenous base (a, u, G, c)
3. Species: DNA and RNA
Type abbreviation basic unit location
Deoxyribonucleic acid DNA deoxynucleotides (4 kinds) are mainly in the nucleus
(a few in chloroplast and mitochondria)
RNA ribonucleotides (4 kinds) mainly exist in cytoplasm
4. Physiological function: store genetic information and control protein synthesis
The genetic material of prokaryotes and eukaryotes is DNA. The genetic material of viruses is DNA or RNA
Chapter 3 cell structure and function
The basic unit of life activity cell
1、 Establishment and development of cell theory
&#The scientist who invented the microscope was Levin hook of Holland;
 the scientist who discovered the cell was hooker of England;
&#Schleiden and Schleiden of Germany founded the cell theory. Schleiden and Schleiden put forward that "all animals and plants are composed of cells, and cells are the basic units of all animals and plants"
&#On this basis, weiershaw of Germany summed up that "cell can only come from cell", and cell is a relatively independent basic unit of life activities, which is considered to be an important supplement to the cell theory
2、 Use of optical microscope
1. Methods:
First aim: one turn converter; two turn concentrator; three turn reflector
Re observation: first place the center of the sample hole; second place the upper part of the object lens; third place the lens barrel to look carefully
2. Note:
(1) Magnification = magnification of objective lens × magnification of eyepiece
(2) The longer the objective, the greater the magnification
The shorter the eyepiece, the greater the magnification
The shorter the "objective glass specimen", the greater the magnification
(3) The image and the actual material are upside down, left and right
(4) Use order of high power objective lens:
Low power mirror → specimen moved to the center → high power mirror → large aperture, concave mirror → fine quasi focus spiral
(5) Judgment of stain position: moving or rotating method
Section 2 cell type and structure
1、 Cell types
Prokaryotic cell: a cell without typical nucleus, nuclear membrane and nucleolus, such as bacteria, cyanobacteria, actinomycetes and other prokaryotes
Eukaryotic cell: an obvious nucleus with a nuclear envelope, such as the cells of animals, plants, and fungi (yeasts, molds, and edible fungi)
2、 Cell structure
1. Cell membrane
(1) Composition: mainly composed of phospholipid bilayer (basic skeleton) and protein, and glycoprotein (outside the membrane)
(2) Structural features: it has certain fluidity (reason: the movement of phospholipid and protein);
Features: selective permeability
(3) Function: protect and control material in and out
2. Cell wall: the main component is cellulose, which has the function of support and protection
3. Cytoplasm: cytoplasmic matrix and organelle
(1) Cytoplasmic matrix: it provides a place and material for metabolism and certain environmental conditions, affecting cell shape, division, movement and organelle transport
(2) Organelles:
 mitochondrion (bilayer membrane): the inner membrane protrudes inward to form a "ridge", the main site of aerobic respiration (the second and third stages), containing a small amount of DNA
 chloroplast (bilayer membrane): it only exists in green cells of plants. There are pigments on Thylakoid, and enzymes related to photosynthesis are contained in thylakoid and matrix. It is the site of photosynthesis and contains a small amount of DNA
&#Endoplasmic reticulum is the workshop of organic synthesis and the channel of protein transport
 Golgi apparatus (monolayer): related to secretion formation in animal cells and mitotic cell wall formation in plants
&#Vacuole (monolayer membrane): vacuole structure. Mature plants have large vacuoles. Functions: store (nutrition, pigment, etc.), maintain cell morphology, regulate osmotic absorption
&#Ribosome (membrane free structure): the site of protein synthesis
&#Centrosome (membranous structure): composed of two vertical centrioles, related to animal cell mitosis
Summary:
Double membrane organelles: mitochondria, chloroplasts
The organelles of monolayer: endoplasmic reticulum, Golgi apparatus, vacuole
Non membrane organelles: ribosome and centrosome;
The organelles containing a small amount of DNA: mitochondria and chloroplasts
The organelles containing pigment: chloroplast and vacuole
Differences between animal and plant cells: centrosomes peculiar to animals; cell walls, chloroplasts and vacuoles peculiar to higher plants
4. Nucleus
(1) Composition: nuclear membrane, nucleolus and chromatin
(2) Nuclear membrane: bilayer membrane with nuclear pore (material exchange channel between nucleus and cytoplasm, RNA, protein and other macromolecules must pass through nuclear pore)
(3) Nucleolus: periodic disappearance (prophase) and reconstruction (telophase) in mitosis
(4) Chromatin: substance dyed dark by basic dyes, consisting mainly of DNA and proteins
The relationship between chromatin and chromosome: two forms of the same substance in a cell at different stages
(5) Function: it is the main place of DNA storage and replication, and the control center of cell genetic characteristics and metabolic activities
(6) The fundamental difference between prokaryotic cells and eukaryotic cells: whether they have formed nuclei (whether they have nuclear membranes)
5. Cell integrity: cells can complete all kinds of life activities only by maintaining the above structural integrity
Section 3 transmembrane transport of substances
1、 The transport mode of substances across membrane is as follows
1. The mode of transmembrane transport of small molecules is as follows
Examples of mode concentration carrier energy