Unit 1. Organization of living things

The TEST will be next Monday, 10th October 2022.

UNIT 1. THE ORGANIZATION OF LIVING THINGS

All living things are made up of cells. Cells are the basic units of life and they carry out the vital functions : nutrition, interaction and reproduction.

ANIMAL CELLS

·       NUCLEUS: controls the cell´s activities

·        CYTOPLASM: is a thick and clear liquid protected by the membrane. It is water and salt and contains organelles.

·       ORGANELLES: There are different ones and each of them is in charge of a different function.

VACUOLES: are a type of organelle in charge of the nutrition function.

·        MEMBRANE: surrounds and protects the cell. The nucleus and the cytoplasm are inside it. 

PLANT CELLS

·        CELL WALLS: it is a rigid wall around the membrane to support the plant.

·        CYTOPLASM: it is the liquid part that contains organelles such as the CHLOROPLASTS that contains a green substance called chlorophyll that help the plan to carry out the photosynthesis.

·        VACUOLE: it is a organelle that contains water, nutrients or waste products.

·        NUCLEUS: controls the cell´s activities. 

Unicellular organisms are made up of 1 cell. For example: bacteria and yeast. 

Multicellular organisms have many cells. For example: plants and animals.

THE ORGANISATION OF ANIMALS

Animals are multicellular organisms that means that are  groups of cells that work together to carry out different functions.

CELLS: are different shapes depending on their functions

TISSUE: is a group of cells and each tissue has a different function.

ORGANS: are made of different tissues

SYSTEMS: are made of different organs that work together to perform a function. For example the Circulatory system that is made up of the heart, blood vessels…

EXAMPLES OF CELLS:

·        RED BLOOD CELLS: They are flat and circular. They carry oxygen from the lungs to the muscles and organs. Then they travel back to the lungs to carry oxygen again.

·        NERVE CELLS: They are star shaped. They transmit nerve impulses from different parts of the body to the brain

.·        REPRODUCTIVE CELLS: They allow us to reproduce. Female reproductive cells are spherical and male cells are oval with a long tail. When both cells combine it is the fertilization. 

THE ORGANIZATION OF PLANTS

Plants are multicellular organisms that means that are  groups of cells that work together to carry out different functions.

CELLS: have a rigid cell wall and they make their own food using the photosynthesis.  They transform water, sunlight, mineral salts and carbon dioxide into nutrients.  They carry out this in the leaf cells and the need a green substance called chlorophyll that it is in the chloroplasts. The water and the minerals salt are in the vacuole.

TISSUE: is a group of cells and each tissue has a different role: protection, supporting the plant, transportation of nutrients…

ORGANS: are made of different tissues. A leaf is an organ that has a specific function, for example to absorb sunlight and carbon dioxide.

SYSTEMS: are made of different organs that work together to perform a function.

PARTS OF A PLANT

·        STEM: supports the plant and transport the water, nutrients and mineral salts throughout the plant

·        ROOTS : its function is to absorb water and nutrients from the soil. To do it, root cells have root hairs to absorb more water and minerals.

·        LEAVES: its function is to make food. They are made up of different tissues and cells. 

LIFE PROCESSES IN ANIMALS

All animals carry out the three vital functions of NUTRITION. INTERACTION and REPRODUCTION.

·        NUTRITION: All living things take in nutrients.

Vertebrates use:

•  the digestive system to extract nutrients. 
•  the respiratory system to obtain oxygen and expel carbon dioxide.
•  the circulatory system to transport the nutrients. 
•  the excretory system to expel waste products.  

·        INTERACTION: Animals detect information in their environment. They use their locomotor system and the nervous system and the sense organs. 

·        REPRODUCTION: animals can create new members of their own species.  There are two reproductive processes: SEXUAL and ASEXUAL. Most animals use SEXUAL reproduction that can be:

o   VIVIPAROUS: they baby grows inside the mother´s belly.

o   OVIPAROUS: they lay eggs.

o   OVIVIVIPAROUS: they reproduce through eggs that hatch inside the mother´s body.

 LIFE PROCESSES IN PLANTS

All plants carry out the three vital functions of NUTRITION. INTERACTION and REPRODUCTION

·        NUTRITION: Plants make their own food using photosynthesis.

1.      The roots absorbs water and minerals form the soil to make RAW SAP.

2.      The raw sap travels up the stem to the leaves.

3.      In the leaves there are small holes called STOMATA that during the photosynthesis they absorb carbon dioxide and expel oxygen (transpiration)

4.      Then the photosynthesis takes place in the leaves using the sunlight and carbon dioxide to convert raw sap into elaborated sap. The elaborated sap contains the nutrients for the plant.

5.      The elaborated sap travels down the stem to other parts of the plant.

 ·        INTERACTION:  Plants interact with the environment. They are anchor to the ground so they can not move around but their roots grow towers the water and nutrients. And also leaves move to the sunlight. 

·        REPRODUCTION: Plants can have seeds or not.

o   Seed plants: some seeds plants can produce flowers and fruits. When a flower is pollinated it produced a fruit and inside the fruit there is a seed. When the seed fall to the ground a new plant grows.

o   Non-seed plants: don’t produce seeds.§  Mosses: reproduce by producing capsules.§  Ferns: reproduce by producing special cells called spores.