1. Cells are the basic units of life activities.
Explain the basic structure and function of microscope.
Optical microscope is used to observe the micro-structure of micro-organisms or organisms. The structure of microscope includes: eyepiece, lens barrel, objective lens, converter, stage, shutter, reflector, fine focusing screw, coarse focusing screw, arm and column. (Volume I P 17)
Using microscope and imitation to make temporary film
(1) In the experiment of practicing using a microscope, you should hold the mirror arm with one hand and the mirror base with the other, not one hand.
Before observation, observe from the side, turn the coarse focusing screw to lower the lens barrel to the lowest point, then turn the coarse focusing screw in the opposite direction of the eyepiece, and stop turning the coarse focusing screw when a rough object image is observed. If it is unclear, turn the fine focusing screw again until a clear object image is observed.
(2) There is a microscope, the magnification of the eyepiece is 10x, and the magnification of the objective lens is 45x. There is a stain in the field of view of the microscope. Is there any way to judge whether the stain is on the eyepiece, the component or the objective lens?
Answer: When the film moves, the stain also moves, indicating that the stain is on the film. Move the film, the stain will not move, indicating that the stain is on the eyepiece or objective lens. Change the objective lens, the stain is gone, indicating that the stain is on the objective lens; Change the objective lens, the stain is still there, which means the stain is on the eyepiece.
(3) Put a piece of white paper with the word "Shang" written on it and observe it under a microscope. What you observe is _ _ _ _ _ _, indicating that the object of observation is to clarify that cells are the basic structure and functional unit of life activities.
Except viruses, most living things are made up of cells. Cell is the basic structure and functional unit of life activities.
The main differences of cell structure between animals and plants from reflection.
* * * has structure: cell membrane, cytoplasm and nucleus. Plant-specific structure: vacuole, cell wall, chloroplast.
. Describe the important role of nucleus in biological heredity.
It is the control center of cell life activities. The genetic material is mainly deoxyribonucleic acid (DNA)
2. Cells divide and differentiate to form tissues, and describe the basic process of cell division.
The process by which a cell divides into two cells. Cells before division are called mother cells, and new cells formed after division are called daughter cells. Cell division usually includes two steps: nuclear division and cytoplasmic division. In the process of nuclear division, the mother cell transfers genetic material to the daughter cell. In unicellular organisms, cell division is the reproduction of individuals, while in multicellular organisms, cell division is the basis of individual growth, development and reproduction. Among them, chromosome changes are the most obvious, and two copies with the same number and shape are formed by replication, and they enter two new cells with cell division.
Identify several basic tissues of human body
Epithelial tissue: protects the internal structure, including the outer surface of the skin and the inner surface of some organs in the body.
Muscle tissue: contraction and relaxation of skeletal muscle, cardiac muscle and smooth muscle.
Nerve tissue: Excitement is mainly composed of nerve cells.
Connective tissue: Support, nutrition, connection and protection include blood, fat, bone tissue and tendons.
Identify several main tissues of plants
Meristem: it has the ability to divide; Protection organization: protection function; Basic organization: storage of nutrition
Transport organization: transport water, inorganic salts and organic nutrients; Mechanical organization: auxiliary role
3. Structural levels of multicellular organisms
Describe the structural levels of green flowering plants: cells → tissues → organs → individuals.
Describe the structural levels of human body: cells → tissues → organs → systems → individuals.