This book is an introduction to biology. It introduces cell, heredity, evolution and biodiversity, behavior and ecology with concrete examples around it. The feature of this book is a detailed introduction to biological problems closely related to human life.

Chapter 1 Introduction: Biology and You 1

1. 1 What is life? 2

Living things need matter and energy to survive 2.

1. 1.2 organisms need complex regulatory mechanisms to maintain their existence 3

1. 1.3 In the face of stimulation, organisms will respond and protect themselves.

1. 1.4 biological growth 4

1. 1.5 Biological reproduction 5

1. 1.6 All living things have the ability to evolve.

1.2 What is evolution? six

Three steps of biological evolution 6

1.3 How do scientists conduct biological research? eight

All aspects of biological research

1.3.2 biologists classify organisms according to their genetic relationship in the process of evolution.

1.4 What is science? 1 1

1.4. 1 Science is based on the following axiom: all natural events have a cause 1 1.

1.4.2 scientific research needs a lot of scientific methods as tools 12

1.4.3 biologists use controlled experiments to verify the hypothesis 12.

1.4.4 The biological theory has been strictly verified 12.

1.4.5 science is human activity 13

The first cell is the basic unit of life.

Chapter II Atoms, Molecules and Life 16

2. 1 What is an atom? 17

2. 1. 1 atom is the basic structural unit of 17 element.

2. 1.2 atoms are composed of smaller particles 17.

2. 1.3 element is defined by atomic number.

2. 1.4 isotope refers to the same element with the same number of protons but different numbers of neutrons 18.

2. 1.5 Interdependence of Nuclei and Electrons in Atoms 18

2.2 How do atoms interact to form molecules? 20

2.2. 1 atom forms molecules to fill vacancies in the outer electron shell 20.

2.2.2 Molecules 20 are formed by chemical bonds between atoms.

2.2.3 Ionic bond 2 1 can be formed between ions.

2.2.4 *** Valence bond enjoys the formation of electrons between atoms through * * * 22.

2.2.5 Polar molecules or nonpolar molecules 22 may be formed by valence bonds between atoms.

2.2.6 Hydrogen bonds are attractive forces between molecules with specific polarities.

2.3 Why is water so important to life? 23

2.3. 1 Mutual attraction between water molecules 24

2.3.2 Water molecules can interact with other biological macromolecules 24

2.3.3 Water can keep the temperature constant.

2.3.4 Water can form a special solid-ice 26.

2.3.5 The aqueous solution can be acidic, alkaline or neutral.

Chapter III Biological Macromolecules 29

3. 1 Why is carbon essential in biomacromolecules? 30

3. 1. 1 The complexity and diversity of organic molecules are determined by the chemical bonds formed between carbon atoms.

3.2 How are organic molecules formed? 3 1

3.2. 1 polymer is usually formed by dehydration reaction and decomposed by hydrolysis reaction.

3.3 What are carbohydrates? 32

3.3. 1 Different monosaccharides have the same molecular formula and different structures 33

3.3.2 disaccharide is formed by connecting two monosaccharides through dehydration reaction.

3.3.3 Polysaccharide is a chain structure 34 formed by combining multiple monosaccharides.

3.4 What is lipid? 36

3.4. 1 Grease, fat and wax are lipids containing only three elements: carbon, hydrogen and oxygen.

3.4.2 Phospholipids contain hydrophilic head groups and hydrophobic tail groups 37.

3.4.3 Sterols contain four bonded carbon rings 38.

3.5 What is protein? 38

3.5. 1 protein consists of long amino acid chains.

3.5.2 Amino acids combine through dehydration reaction to form protein 40.

3.5.3 protein can form a four-level structure 40 at most.

3.5.4 The function of protein is related to its three-dimensional structure.

3.6 What are nucleotides and nucleic acids? Forty two.

3.6. 1 nucleotide can be used as a carrier of energy storage and a messenger of intracellular signal transduction.

3.6.2 DNA and RNA are both nucleic acids and genetic materials.

Chapter IV Structure and Function of Cells

4. 1 What is cell theory? 45

4.2 What are the basic characteristics of cells? 45

4.2. 1 All cells have the same characteristics as * * * 45.

4.2.2 There are two basic types of cells: prokaryotic cells and eukaryotic cells.

4.3 What are the main characteristics of eukaryotic cells? Forty nine

4.3. 1 Some eukaryotic cells need to rely on the cell wall to support the cell structure 50.

4.3.2 Cytoskeleton maintains cell morphology, supports cell structure and regulates cell movement.

4.3.3 Flagella and cilia make the cells move in the direction of liquid flow, or make the liquid flow across the cell surface 5 1.

4.3.4 The nucleus contains DNA and is the control center of eukaryotic cells.

4.3.5 The membrane structure in the cytoplasm of eukaryotic cells forms the endomembrane system 54 in the cells.

4.3.6 Vacuoles have many functions, including regulating water balance, storing substances and supporting cell structure.

4.3.7 Mitochondria get energy from food, while chloroplasts can directly capture solar energy.

4.3.8 Plants sometimes use plastids (or pigments) to store energy 60.

4.4 What are the main characteristics of prokaryotic cells? 60

4.4. 1 The cell surface of prokaryotic cells is very special 6 1.

4.4.2 Compared with eukaryotic cells, the cytoplasm structure of prokaryotic cells is simpler.

Chapter V Structure and Function of Cell Membrane

5. 1 How is the structure of cell membrane related to its function? 64

5. 1. 1 Cell membrane is a "flowing mosaic structure", and protein is constantly moving in the lipid molecular layer.

5. 1.2 phospholipid bilayer isolates the cell contents from the outside world.

5. 1.3 A plurality of protein forms a mosaic pattern 66 on the cell membrane.

5.2 How does the substance cross the cell membrane? 67

5.2. 1 gradient makes molecules in the fluid diffuse.

5.2.2 Transmembrane transportation includes passive transportation and energy-consuming transportation.

5.2.3 Passive transportation includes simple diffusion, cooperative diffusion and infiltration.

5.2.4 Energy consumption transportation includes active transportation, endocytosis and exocytosis 7 1.

5.2.5 Transmembrane substance exchange affects the size and shape of cells 74

5.3 How do specialized connections connect and communicate with cells? 74

5.3. 1 desmosomes adhere cells together 74

5.3.2 Close connection makes the batteries adhere to each other without leakage 75.

5.3.3 Gap junction and plasmodesmata enable direct communication between cells.

Chapter VI Energy Flow in Cells 76

6. 1 What is energy? 77

6. 1. 1 Thermodynamic laws describe the basic characteristics of energy.

6. 1.2 Bio-utilization of solar energy to create a low-entropy environment for life 78

6.2 How is energy converted in chemical reaction? 79

6.2. 1 Energy released by energy release reaction 79

6.2.2 Energy absorption reaction requires energy absorption 79

6.3 How is intracellular energy transported? 80

6.3. 1 ATP and electron carrier are intracellular energy-carrying molecules 80.

6.3.2 Coupling reaction links energy release reaction and energy absorption reaction 8 1.

6.4 How do enzymes catalyze biochemical reactions? 82

6.4. 1 catalyst reduces the energy required to start the reaction 82.

6.4.2 Enzymes are biocatalysts 82

6.5 How is the biological enzyme regulated? 84

6.5. 1 Cells regulate metabolic pathways by controlling the synthesis and activation of biological enzymes.

6.5.2 Toxic substances, drugs and environmental factors will all affect the enzyme activity.

Chapter 7 Photosynthesis: Solar Trap 89

7. 1 What is photosynthesis? 90

7. 1. 1 Chlorophyll in leaves and leaves is a necessary condition for photosynthesis.

7. 1.2 Photosynthesis consists of photoreaction and Kelvin cycle.

7.2 Photoreaction stage: How is light energy converted into chemical energy? 92

7.2. 1 Pigment 92 in chloroplast captures light energy.

7.2.2 The photoreaction stage occurs on the membrane structure of the base particle 94.

7.3 Kelvin Cycle: How is the chemical energy stored in sugar molecules? 96

7.3. 1 kelvin cycle capture carbon dioxide 97

7.3.2 Carbon fixed in Kelvin cycle is used to synthesize glucose 97.

Chapter 8 Energy Acquisition: Glycolysis and Cell Breathing 99

8. 1 How do cells get energy? 100

8. 1. 1 The energy produced by photosynthesis is the ultimate source of cell energy.

8. 1.2 Glucose is the main energy storage molecule 10 1.

8.2 What is glycolysis? 10 1

8.3 What is the respiration of cells? 102

8.3. 1 In the first phase of cell respiration, pyruvate is decomposed by 102.

8.3.2 In the second phase of cell respiration, high-energy electrons will pass through the electron transfer chain 103.

8.3.3 In the third stage of cell respiration, ATP is formed by chemical osmosis 103.

8.3.4 Cell respiration can obtain energy from various molecules 105.

8.4 How does fermentation happen? 105

8.4. 1 In an anaerobic environment, cells can recover NAD by fermentation.

8.4.2 Some cells decompose pyruvate into lactic acid 105 by fermentation.

8.4.3 Some cells convert pyruvate into ethanol and carbon dioxide through fermentation.

The second legacy

Chapter 9 Life Continuation: Cell Proliferation 108

9. 1 Why do cells divide? 109

9. 1. 1 Cell division transmits genetic information to each daughter cell 109.

Cell division is necessary for growth and development.

9. 1.3 Cell division is necessary for sexual reproduction and asexual reproduction 1 10

9.2 What is the cell cycle of prokaryotic cells? 1 1 1

9.3 How are the DNA molecules of eukaryotic cells arranged? 1 12

9.3. 1 The chromosome of eukaryotic cell consists of a linear DNA double helix molecule and a protein connected to it.

9.3.2 Gene is a DNA fragment on chromosome 1 13.

9.3.3 A pair of duplicated chromosomes are separated by 1 13 during cell division.

9.3.4 Eukaryotic chromosomes usually appear in pairs and contain the same genetic information 1 14.

9.4 How does the cell cycle of eukaryotic cells occur? 1 16

9.4. 1 The cell cycle of eukaryotic cells includes interphase and mitosis 1 16.

9.5 How do cells produce two daughter cells with the same genetic background through mitosis? 1 17

9.5. 1 In the prophase of mitosis, chromosomes are compressed to form spindle microtubules structure, the nuclear membrane is broken, and chromosomes are interrelated.

Spindle microtubules is connected with 1 17.

9.5.2 In the metaphase of mitosis, chromosomes are arranged on the equatorial plate of 1 19 cells.

9.5.3 At the end of mitosis, sister chromatids are separated and pulled to the two poles of the cell 1 19.

9.5.4 At the end of mitosis, a nuclear membrane structure of 1 19 will be formed around each chromosome group.

The original "Biology and Life", version 10, Teresa Odsk is waiting.