5 biology questions in the first year of junior high school, about a few biology junior high school

1.The pericarp is developed from the ovary wall, and the seed coat is developed from the beads.

The role of the pericarp during seed development can be seen as the role of the ovary wall, that is, to protect the ovule and make the seed develop normally;

The pericarp acts after the seeds are ripe:

1) Protect delicate immature seeds.

2) Assist in the dispersal of seeds after they are ripe (for example, some peels become thorny, and when an animal passes by, it will stick to it, so that the seeds will go with the animal to other places.) There are also peels that turn into soft flocculents that can fly in the wind, like dandelions. ）

The role of the seed coat is to protect the seed and provide nutrients to the seed.

2.It is a fruit, and the inner beads of corn are healed together by the residual seed coat and peel developed by the inner layer cells, which is called Yingguo, which is a unique fruit type of grasses.

The seeds of corn are in the fruit, but the peel and seed coat are connected together during the development process, so the seed of corn is the part of the corn kernel that has removed the peel.

3.Protective mulch for plants or animals. In plants, the beads are formed into a envelope outside the ovules. The beads will be developed into seed coats.

4.Mung bean grains, cotyledons, sesame grains, endosperm, almond cotyledons.

5.Yes peel.

1 The coat is developed from beads.

The peel is, developed from the wall of the ovary.

I only understand this, and I have long forgotten about the others, hehe.

1. There are three conditions for seed germination: suitable temperature, suitable water and light.

2. Autotrophic: like green plants, use the organic matter made by themselves to maintain the nutritional mode of life, heterotrophic: can not directly synthesize inorganic matter into organic matter, must ingest ready-made organic matter to maintain the nutritional mode of life, such as people, animals.

Parasitism: Two organisms live together, one party benefits, the other party suffers, and the latter provides nutrients and living places for the former, the relationship between this organism is called parasitism, such as roundworms and humans are parasitic relationships.

3.Choose A. Mice are homeothermic animals. Frogs are ectotherms. In a cold environment, homeothermic animals need to maintain their body temperature by consuming energy and producing heat, and their oxygen consumption increases.

Like green plants, the nutritional method of using self-produced organic matter to maintain life is called autotrophic, and it is an important characteristic common to all kinds of green plants. Able to self-nourish; In particular, it refers to the only ** that can use carbon dioxide or carbonate as carbon, and can be synthesized by simple inorganic nitrogen metabolism - generally green plants, some chemoautotrophic bacteria and protoplasm; For normal metabolism, no specific external factors are required.

It is not possible to directly synthesize inorganic matter into organic matter, but must ingest ready-made organic matter to maintain life, which is called heterotrophic. Heterotrophic includes three modes: symbiotic, parasitic, and saprophytic.

Parasitism (parastisu) is the relationship between two organisms living together, one party benefits, the other party suffers, and the latter provides nutrients and a place to live for the former, and this biological relationship is called parasitism. The main parasites are bacteria, viruses, fungi, and protozoa. Among animals, parasitic worms are particularly important, while insects are the main large parasites of plants.

Obligate parasitism must be nourished by the host**, and facultative parasitism can also operate freely. Parasitoids are a large group of insect macroparasites that lay eggs on or in the body of an insect host, often resulting in host death.

Yeast is a microorganism, not a plant, an animal.

c The cell wall is endemic to plants and microorganisms, and humans do not chloroplasts are endemic to green plants and photosynthetic bacteria.

**Large vacuoles are unique to plants and are used for dialysis with the outside world, so they do not contain 136

c Cell differentiation, as defined in the book, is irreversible.

The teacher told us that the answer was 100% correct! )

The control group was C, and the experimental group was A and B.

4) Left to right.

5) Because the osmotic pressure on the salt side is greater than that of the paramecium itself, it can avoid damage.

It is beneficial for its brightness.

Paramecium can take advantage of the pants to avoid damage.