The first biological chapter 1 knowledge points

The first chapter of junior one biology summarizes knowledge points, makes rational reflection on learning methods, strengthens migration, and grasps learning methods in training. The following is my summary of the knowledge points in the first chapter of the first volume of junior high school mathematics, hoping to help everyone.

I. Positive Numbers and Negative Numbers

1, a number other than 0 I learned before plus a negative sign-called a negative number.

2. The numbers other than 0 that I learned before are called positive numbers.

3. Zero is neither positive nor negative, and zero is the dividing line between positive and negative numbers.

4. In the same problem, positive numbers and negative numbers have opposite meanings.

Second, rational numbers.

1, positive integers, 0 and negative integers are collectively called integers, and positive and negative fractions are collectively called fractions.

2. Integers and fractions are collectively called rational numbers.

3. Put a number together to form a set of numbers, which is called number set for short.

Third, the number axis

1, and the straight line defining the origin, positive direction and unit length is called the number axis.

2. Function of the number axis: All rational numbers can be represented by points on the number axis.

3. Note: The origin, positive direction and unit length of (1) axis are indispensable.

⑵ The unit length of the same shaft cannot be changed.

4. Attribute: Of the two numbers represented on the (1) number axis, the number on the right is always greater than the number on the left.

(2) Positive numbers are all greater than zero, negative numbers are all less than zero, and positive numbers are greater than negative numbers.

Fourth, the inverse number

1, only two numbers with different signs are called reciprocal.

2. The two points representing the opposite number on the number axis are symmetrical about the origin.

The reciprocal of zero is zero.

Absolute value of verb (abbreviation of verb)

1. The distance between the point representing the number A on the general number axis and the origin is called the absolute value of the number A, and it is recorded as |a|.

2. The absolute value of a positive number is itself; The absolute value of a negative number is its reciprocal; The absolute value of 0 is 0.

6. Comparison of rational numbers

1, positive number is greater than 0, 0 is greater than negative number, positive number is greater than negative number.

2, two negative numbers, the absolute value is big but small.

Seven, the addition of rational numbers

1, the addition rule of rational numbers

Add two numbers of (1), take the same sign, and then add the absolute values.

(2) Add two numbers with different absolute values, take the sign of the addend with larger absolute value, and subtract the one with smaller absolute value from the one with larger absolute value.

(3) Two opposite numbers add up to get zero.

(4) When a number is added to zero, the number is still obtained.

2. Arithmetic of rational number addition

(1) additive commutative law: Two numbers are added, the addend positions are exchanged, and the sum is unchanged. That is, a+b = b+a.

(2) The law of addition and association: When three numbers are added, the first two numbers are added, or the last two numbers are added first, and the sum is unchanged. That is, (a+b)+c=a+(b+c)

Eight, subtraction of rational numbers

1, rational number subtraction rule

Subtracting a number is equal to adding the reciprocal of this number. That is, a-b=a+(-b)

Nine, multiplication of rational numbers

1, multiplication rule of rational numbers

(1) Multiply two numbers, the same sign is positive, the different sign is negative, and the absolute value is multiplied.

(2) Any number multiplied by 0 will get 0.

(3) Two numbers whose product is 1 are reciprocal.

(4) Multiply several numbers that are not zero, and when the number of negative factors is even, the product is positive; When the number of negative factors is odd, the product is negative.

(5) When several numbers are multiplied, if one factor is zero, the product is zero.

2. Arithmetic of rational number multiplication

(1) Multiplication Commutativity Law: When two numbers are multiplied, the positions of the exchange factor and the product are equal. Namely ab=ba

(2) Multiplication and association law: When three numbers are multiplied, the first two numbers are multiplied first, or the last two numbers are multiplied first, and the products are equal. That is, (ab)c=a(bc)

(3) Multiplication and distribution law: a number is multiplied by the sum of two numbers, which means that this number is multiplied by these two numbers respectively, and then the products are added. That is, a(b+c)=ab+ac.

Division of rational numbers

1, rational number division rule

(1) divided by a number that is not equal to 0 is equal to multiplying the reciprocal of this number.

(2) Zero cannot be divided.

(3) Divide two numbers, the one with the same sign is positive, and the one with different signs is negative, and divide by the absolute value.

(4) Divide 0 by any number that is not equal to 0 to get 0.

Xi。 Power of rational number

1, the operation of finding the product of n identical factors is called power, and the result of power is called power. In, a is called the base and n is called the exponent. When an is regarded as the result of the n power of a, it can also be read as the n power of a. ..

2. The odd power of a negative number is negative, and the even power of a negative number is positive.

3. Any power of a positive number is a positive number and any power of a positive integer is 0.

Twelve, rational number mixed operation operation order

1, calculate the power first, then multiply and divide, and finally add and subtract;

2. Unipolar operation, from left to right;

3. If there are brackets, do the operation in brackets first, and then follow the brackets, brackets and braces in turn.

Thirteen, scientific notation

1, numbers greater than 10 are expressed as a 10n (where a is a number with only one integer bit and n is a positive integer), and scientific notation is used.

2. Use scientific notation to represent n-bit integers, where the exponent of 10 is n- 1.

14. Approximate values and significant figures

1, which is close to the actual number, but still different from the actual number, is called a divisor.

2. Accuracy: If an approximate number is rounded, it means it is accurate.

3. From the first non-zero digit to the last digit on the left of a number, all digits are valid digits of this number.

4. For the number a 10n expressed by scientific notation, its effective number is specified as the effective number in A. ..

The first biological chapter 1 knowledge points

First of all, linear animals

1, representing animals: mainly including roundworms, Caenorhabditis elegans (living freely), hookworms, filariasis, pinworm, etc.

2. Ascaris: (There are four characteristics of Ascaris suitable for parasitism, red)

① Living habits: Parasitic in human small intestine, living by sucking semi-digested chyme in small intestine.

② Morphology: Ascaris has a cylinder. There is a mouth at the front end, an anus at the back end, and a cuticle on the body surface (protection). The tail of the male ascaris is hooked, the tail of the female ascaris is straight, and the male worm is slightly shorter than the female worm.

③ Digestion: The digestive tube is simple in structure, and the intestine consists of only one layer of cells.

④ Reproduction: The reproductive organs are developed and the reproductive ability is strong. Female worms can lay about 200,000 eggs every day, and ascaris lumbricoides fertilized eggs develop into larvae for about two weeks.

⑤ Exercise: There is no special exercise organ.

⑥ Infection: through oral cavity.

⑦ Prevention of ascariasis: First of all, we must pay attention to personal food hygiene, do not drink unclean raw water, do not wash vegetables and fruits, and wash our hands before and after meals; Secondly, we should manage the feces well, and the feces can only be used as fertilizer after being treated to kill the eggs.

The reasons why children are prone to ascariasis: they don't develop good hygiene habits and like to eat raw and cold food; I like playing on the ground and sucking my fingers. Poor resistance.

3. The main characteristics of linear animals are: slender cylindrical body with cuticle, mouth and anus.

Second, annelids.

1, representing animals: earthworm, nereis, leech.

2. Earthworms:

① Morphological structure: cylindrical, composed of many similar segments, with a ring at the front end (with reproductive function), and a *** 13 segment from the front end of earthworm to the ring.

② Exercise: There are well-developed muscles on the body wall, which make the body crawl through the cooperation of muscles and bristles. Dividing the body can enhance the flexibility of exercise. Bristles can't work on glass, so earthworms can't move on glass. Bristles are located on the ventral surface and are used to support and fix the body and assist in movement.

③ Living habits: Living in moist, loose soil rich in organic matter, digging holes in the soil during the day, feeding on the organic matter in the soil, and climbing out of the ground at night. Feed on fallen leaves on the ground

④ Breathing: No special respiratory organs. Breathing (gas exchange) depends on the moist body wall (secretion of mucus) to keep the body wall moist at all times to ensure normal breathing. (In the experiment, use a wet cotton ball soaked in water to gently wipe the earthworm's body surface to keep it moist and maintain normal breathing, but vaseline cannot be used. )

⑤ Food: Organic matter in soil, including humus, animal manure, soil bacteria, etc. And the differentiation products of these substances ⑤ the relationship between earthworms and people: moving in the soil, loosening the soil; Pull out feces to improve soil fertility; The body is rich in protein, which is an excellent feed (advantage) to move in the soil and destroy the roots of plants (disadvantage).

⑦ The reason why earthworms climb out of the ground after heavy rain: Earthworms breathe through wet body walls. After the rain, the ground is full of rain, and there is little oxygen. Earthworms can't breathe, so they climb out of the ground to breathe.

The first biological chapter 1 knowledge points

Unit 1: Biology and Biosphere

1, methods of scientific research:

Observation, investigation, inquiry, experiment and data analysis. ......

The process of scientific inquiry includes the following links:

Ask questions, make assumptions, make plans, implement plans, draw conclusions and express communication.

Hypothesis: it is a hypothesis made on the proposed question and a prediction of the result of the question. Assumptions are based on observation and existing knowledge and experience.

When making a plan, we should pay attention to controlling a single variable and setting up control experiments.

2. Biological characteristics

1) organisms need nutrition: most plants produce organic matter through photosynthesis (autotrophic); Animals get ready-made nutrition (heterotrophy) from the outside.

2) living things can breathe.

3) Organisms can excrete wastes from their bodies.

The way animals excrete waste: sweating, exhaling and urinating. The way plants excrete waste: fallen leaves.

4) Organisms can respond to external stimuli-stress. Exodus: The zebra flees quickly after discovering the enemy's harm. The response of mimosa to stimulation. Sunflowers are blooming towards the sun.

5) Organisms can grow and reproduce.

6) Biology has the characteristics of heredity and variation.

7) Except viruses, all living things are made up of cells.

3. Scope of the biosphere: the bottom of the atmosphere, most of the hydrosphere and the surface of the lithosphere.

The biosphere is a unified whole.

4. Basic conditions (abiotic factors) provided by biosphere for living things: nutrients, sunlight, air and water, suitable temperature and certain living space.

5. Environmental factors-ecological factors affecting biological survival include:

Abiotic factors: light, temperature, moisture, etc. Biological factors: other organisms that affect the life of a certain organism.

Exodus: Ladybug septempunctata preys on aphids, which is a predatory relationship. Weeds and rice in rice fields compete for sunlight, which is a competitive relationship. Division and cooperation of family members of ants and bees.

6, biological adaptation and the impact on the environment:

1) Examples of biological adaptation to the environment: camels in the desert have little urine; The underground roots of Alhagi are much longer than the aboveground parts; Seals in cold seas have thick subcutaneous fat on their chests; Flag trees, etc.

2) Biological impact on the environment: Earthworms move in the soil, which can loosen the soil, and their feces increase the fertility of the soil; Sand plants such as windbreak and sand fixation belong to the biological influence environment. Lichen can accelerate the weathering of rocks, promote the formation of soil layers and play a pioneering role.

7. Concept and composition of ecosystem

Concept: in a certain area, the unified whole formed by biology and environment is called ecosystem.

Composition: including biological part and abiotic part. The biological part includes producers (plants), consumers (animals) and decomposers (bacteria and fungi). Abiotic parts include sunlight, water, air, temperature, etc.

8, food chain and food web:

The relationship between producers and consumers is mainly the relationship between eating and being eaten, thus forming a food chain. The food chain is intertwined to form a food web.

Matter and energy in the ecosystem flow along the food chain and food web, and the characteristics of energy flow in the food chain gradually weaken. Matter circulates repeatedly. Toxic substances can't be decomposed and discharged in organisms, so they will accumulate through the food chain.

When writing the food chain, pay attention: it can only start from producers and stop at consumers. Don't write the resolver.

9. List different ecosystems:

Forest ecosystem, grassland ecosystem, desert ecosystem, marine ecosystem, freshwater ecosystem, wetland ecosystem, farmland ecosystem, etc. The biosphere is an ecosystem. The more species and quantity of organisms in the ecosystem, the stronger the self-regulation ability, and vice versa. The regulation ability of ecosystem is limited. If the external disturbance exceeds this limit, the ecosystem will be destroyed. Human activities are the factors that affect the ecosystem.

Second unit

10, and observe the loading situation with a microscope.

① The eyepiece sees an inverted image. Example: If you see a "D" in the field of vision of a microscope, then "P" is written on transparent paper.

② The magnification of microscope is the product of the magnification of objective lens and eyepiece. 10X30=300

③ When the object image is seen in the lower left field of vision, the specimen should move the object image to the lower left center.

(4) Distinguish the position of the stain: move the film, and the stain will move with it, and the stain will be on the film; Turn the eyepiece, the stain will move with it, and the stain will be on the eyepiece; Move the bracket and eyepiece, the stain will not move, then the stain will be on the objective lens.

Main points of aiming: rotate the coarse focusing screw to raise the lens barrel, and then rotate the converter to aim the low-power objective at the light hole. Turn the shutter to aim a larger aperture at the light hole. Look at the eyepiece with one eye (the other eye is open) and observe while turning the mirror until you see a white circular field of vision.

1 1. Cells are the basic structural and functional units of biological activities. Basic structure and function of cells

① Cell membrane-protects the internal structure of cells and controls the entry and exit of substances inside and outside cells.

② Cytoplasm-The cytoplasm of living cells has fluidity, which is beneficial to the material exchange between cells and the external environment.

③ Nucleus-plays an important role in biological inheritance. The nucleus contains genetic material.

④ Cell wall-support and protection.

12, unique structure of plant cells: cell wall, chloroplast and vacuole. (Not all plant cells have chloroplasts)

13, Preparation and Observation of Onion Epidermal Cell Slices

Manufacturing steps: (1) First, drop a drop of water in the center of a clean glass slide. (2) Tear off a small piece of transparent film from the inner surface of the scale leaf with tweezers. (3) Put the torn film into the water drop in the center of the glass slide and flatten it gently with a dissecting needle. (4) Clamp the edge of one side of a cover glass with tweezers, first touch the other side with water drops, and then gently lay it flat and cover it on the film, which can reduce the generation of bubbles. (5) Iodine staining. (6) Observe under a low-power microscope (in fact, what you see is a small part of the plant protection organization)

Experiment: Observe the main tissues of leaves. The basic steps are the same as above, but dyeing is not needed. Use two clamped blades, a writing brush and clean water when taking materials. Microscopically, the leaf structure includes epidermis (protective tissue), mesophyll (vegetative tissue) and vein (conducting tissue).

14. Preparation and observation of oral epithelial cells

(1) Drop a drop of normal saline in the center of a clean slide. (2) Rinse your mouth with cold boiled water and scrape it gently from the inner side wall of your mouth with a toothpick. (3) Put some crumbs attached to the toothpick in the normal saline on the glass slide for a few drops. (4) Cover the cover glass. (5) Iodine staining. (6) Observe under a low-power microscope.

15, the function of cell membrane: let useful substances enter the cell, keep other substances out of the cell, and at the same time discharge the waste generated in the cell.

Mitochondria and chloroplasts are energy converters in cells.

Chloroplast: converts light energy into chemical energy and stores it in the organic matter it produces.

Mitochondria: release chemical energy from organic matter for use by cells.

17, the role of nucleus in biological inheritance

The control center of a cell is the nucleus. There are chromosomes in the nucleus, DNA in the chromosomes and genetic information in the DNA.

18. Cells produce new cells through division: in the process of division, the nucleus is first divided into two parts, and then the cytoplasm is divided into two parts, each part contains a nucleus. Finally, a new cell membrane is formed in the center of the original cell, and plant cells also form new cell walls. As a result, one cell divides into two cells.

Cell growth: Newborn cells absorb nutrients from the surrounding environment and become their own components, and the volume changes from small to large. During the growth of plant cells, vacuoles change obviously, from small to large (central vacuole).

19. Cells differentiate into tissues.

Five tissues of plants: meristem, conservation, nutrition, transportation and machinery.

The four major tissues of human body: epithelial tissue, nerve tissue, connective tissue and muscle tissue.

Meristem: small cell, large nucleus, thin cell wall and thick cytoplasm. Strong ability to divide, constantly produce new cells, and constantly grow and differentiate to form various implanted tissues.

Protective tissue: cells are closely arranged and have protective function.

Vegetative tissue: thin cell wall, large vacuole, which can store nutrients or contain chloroplasts for photosynthesis.

Mechanical tissue: the cell wall is thickened, which plays a supporting, reinforcing and protecting role.

Transportation organization: It runs through all parts of plants. The conduit can transport water and inorganic salts, and the sieve tube can transport organic matter.

Epithelial tissue: protective and secretory functions.

Muscle tissue: composed of muscle cells, it has the functions of contraction and relaxation, which enables the body to exercise.

Nerve tissue: mainly composed of nerve cells, it can feel stimulation, conduct nerve impulses and play a regulatory role.

Connective tissue: There are many kinds. Function: Support, connection, nutrition, protection and other functions.

20. The structural level of human body: cell → tissue → organ → system → human body.

Cell: It is the basic unit of organism structure and function.

Tissue: produced by cell differentiation. It is a cell group composed of cells with similar morphology, structure and function.

Organ: Different tissues are combined together in a certain order and perform certain functions to form an organ.

System: A system is composed of multiple organs, which can perform one or several physiological functions in a certain order.

The human body has motor system, respiratory system, circulatory system, urinary system, nervous system, endocrine system and reproductive system. Each system cooperates and coordinates with each other to complete various life activities.

2 1. The structural level of plants: cells → tissues → organs → plants (plants are unsystematic).

22. Six organs of green flowering plants: roots, stems, leaves (vegetative organs), flowers, fruits and seeds (reproductive organs).

23. An organism with only one cell.

Yeast, bacteria, paramecium, Chlamydomonas, Eupolyphaga, Amoeba and so on are all single-celled organisms, which can live independently and have all physiological activities.

The main structure of paramecium: surface membrane, nucleus, cytoplasm, oral groove, collecting duct, contraction vesicle, anus and cilia.

The causes of red tide are eutrophication of water and a large number of single-celled organisms.

Harm of red tide and water bloom: Single-celled organisms compete with other aquatic organisms for free oxygen, and excessive accumulation of toxins released by toxic algae and cyanobacteria will cause water deterioration, fish will die of hypoxia or poisoning, endangering fishery production.

Scientific research methods: observation, investigation, inquiry, experiment and data analysis. ......

The process of scientific inquiry includes the following links: asking questions, making assumptions, making plans, implementing plans, drawing conclusions and expressing communication.

Hypothesis: it is a hypothesis made on the proposed question and a prediction of the result of the question. Assumptions are based on observation and existing knowledge and experience.

When making a plan, we should pay attention to controlling a single variable and setting up control experiments.

2. Biological characteristics

1) organisms need nutrition: most plants produce organic matter through photosynthesis (autotrophic); Animals get ready-made nutrition (heterotrophy) from the outside.

2) living things can breathe.

3) Organisms can excrete wastes from their bodies.

The way animals excrete waste: sweating, exhaling and urinating. The way plants excrete waste: fallen leaves.

5) Organisms can grow and reproduce.

6) Biology has the characteristics of heredity and variation.

7) Except viruses, all living things are made up of cells.

3. Scope of the biosphere: the bottom of the atmosphere, most of the hydrosphere and the surface of the lithosphere. The biosphere is a unified whole.

4. Basic conditions (abiotic factors) provided by biosphere for living things: nutrients, sunlight, air and water, suitable temperature and certain living space.

5. Environmental factors-ecological factors affecting biological survival include:

Abiotic factors: light, temperature, moisture, etc. Biological factors: other organisms that affect the life of a certain organism.

6, biological adaptation and the impact on the environment:

7. Concept and composition of ecosystem

Concept: in a certain area, the unified whole formed by biology and environment is called ecosystem.

8, food chain and food web:

The relationship between producers and consumers is mainly the relationship between eating and being eaten, thus forming a food chain. The food chain is intertwined to form a food web.

When writing the food chain, pay attention: it can only start from producers and stop at consumers. Don't write the resolver.

9. List different ecosystems:

10, and observe the loading situation with a microscope.

① The eyepiece sees an inverted image. Example: If you see a "D" in the field of vision of a microscope, then "P" is written on transparent paper.

② The magnification of microscope is the product of the magnification of objective lens and eyepiece. 10X30=300

③ When the object image is seen in the lower left field of vision, the specimen should move the object image to the lower left center.

1 1. Cells are the basic structural and functional units of biological activities. Basic structure and function of cells

① Cell membrane-protects the internal structure of cells and controls the entry and exit of substances inside and outside cells.

② Cytoplasm-The cytoplasm of living cells has fluidity, which is beneficial to the material exchange between cells and the external environment.

③ Nucleus-plays an important role in biological inheritance. The nucleus contains genetic material.

④ Cell wall-support and protection.

12, unique structure of plant cells: cell wall, chloroplast and vacuole. (Not all plant cells have chloroplasts)

13, Preparation and Observation of Onion Epidermal Cell Slices

14. Preparation and observation of oral epithelial cells

15, the function of cell membrane: to protect and control the entry and exit of substances. (Selective permeability)

Mitochondria and chloroplasts are energy converters in cells.

Chloroplast: converts light energy into chemical energy and stores it in the organic matter it produces.

Mitochondria: release chemical energy from organic matter for use by cells.

17, the role of nucleus in biological inheritance

The control center of a cell is the nucleus. There are chromosomes in the nucleus, DNA in the chromosomes and genetic information in the DNA.

To sum up: cells are the unity of matter, energy and information.

19. Cells differentiate into tissues.

Five tissues of plants: meristem, conservation, nutrition, transportation and machinery.

The four major tissues of human body: epithelial tissue, nerve tissue, connective tissue and muscle tissue.

The functional features are as follows:

Meristem: small cell, large nucleus, thin cell wall and thick cytoplasm. Strong ability to divide, constantly produce new cells, and constantly grow and differentiate to form various plant tissues.