Raíces
que
la anclan al suelo. Con ellas absorben agua y minerales del suelo.
Un tallo que la sostiene y a través del que transporta el agua y otras
sustancias desde las raíces a las hojas.
Leaves are the organs of the plant that perform
photosynthesis.
¿Qué necesitan las plantas?
Las plantas son seres vivos,
así que, como tal, necesitan alimento que les de nutrients y energía.
A diferencia de los animales,
las plantas elaboran su propio alimento. Para ello necesitan luz, agua, aire y
sales minerales.
Luz es esencial
para el crecimiento de las plantas. Todas las plantas la necesitan para hacer
su alimento.
Tampoco pueden vivir sin agua, también necesaria para fabricar
su alimento.
Cada planta necesita una
cantidad mayor o menor de agua y luz que otras.
Aire. Las plantas toman dióxido de carbono para
fabricar su alimento y expulsan oxígeno al aire.
Sales Minerales. Normalmente están disueltas en el agua. Las
tierras fértiles y húmedas son ricas en sales minerales. Las tierras pobres son
secas y tienen menos sales minerales.
La temperatura es importante
también.
La nutrición de las plantas
Las plantas toman sustancias
del suelo (agua y sales minerales) y del aire (dióxido de carbono).
Las plantas fabrican su
propio alimento: la savia bruta se combina con el dióxido de
carbono y se transforma en savia elaborada a través de la fotosíntesis.
Los nutrientes son transportados
a través de unos tubos llamados vasos leñosos.
La respiración de las
plantas: Las plantas toman oxígeno y expulsan dióxido de carbono por la noche. A
través de la fotosíntesis toman dióxido de carbono y expulsan oxígeno. Las plantas
combinan el oxígeno con los nutrientes para producir energía y crecer.
Roots anchor plants to the ground. They absorb water and
minerals from the soil.
A stem
holds up the plant and transport water and other substances from the roots to
the leaves.
Leaves are the organs of the plant that perform
photosynthesis.
What do plants need?
Plants are living things, so they need food to get
nutrients and energy.
Unlike animals, plants make their own food. In order
to do this, plants need light, water, air and mineral salts.
Light is essential for plants to grow. All plants need it
to make their food.
Plants cannot live without water, they need it to make their food too.
Each kind of plant need more or less water or light
than others.
Air. Plants take in carbon dioxide to make their food and
throw out oxygen.
Mineral salts. They are usually dissolved in water. Fertile soil is
humid and rich in mineral salts. Poor soil is dry and has less mineral salts.
Temperature is important too.
Plant nutrition
Plants take in substances from the soil (water and
mineral salts) and from air (carbon dioxide).
Plants make their own food: raw sap combines with carbon dioxide and transforms
into elaborated sap through photosynthesis.
Nutrients are transported through tubes called phloem
vessels.
Plants respiration: Plants take in oxygen and release
carbon dioxide day and night. Through photosynthesis plants take in carbon
dioxide and release oxygen during the day. Plants combine oxygen with nutrients
to produce energy for growth.
This video elaborates the process of Photosynthesis, by which plants make their own food.
Photosynthesis
is the process used by the plants to make their food. In simpler terms,
conversion of light energy into chemical energy by plants is called
photosynthesis. This chemical energy is used by the plants for growth
and nourishment. Photo means light and synthesis means putting together.
Humans need some essential things like fire, water, vegetables etc to cook food. Similarly, to make their own food, plants also need some essential factors like Light, water, nutrients, soil etc
Plants
get light from the sun, water from the ground and carbon dioxide from
air. All these factors including air, water, carbondioxide and sunlight
together help plants churn out their own food.
Plants have tubes
called Xylem located in the stem through which the water from the
ground is sucked into the leaves. This system works similar to the
humans sucking in liquids through a straw. The Xylem is spread
throughout the different parts of plant including stem, branches, all
the way upto their leaves, and transports vital nutrients to the entire
plant. Xylems in plants are like blood vessels in the human body that
act as an important means of transport for water and nutrients.
Leaves
on the plants have pores, very similar to pores on the skin of our
body. These pores are called stomata. These stomata are responsible for
the exchange of gases. The carbon dioxide present in the air, which is
responsible for photosynthesis, enters the plant through these stomata.
Oxygen also comes out from the same stomata.
Leaf has important
cells called Mesophyll cells. These cells contain a green color
component called chloroplast. This chloroplast is responsible for the
green color of plants and leaves.
Once the carbon dioxide and
water reach the chloroplasts, in the presence of sunlight, the process
of photosynthesis starts to take place. The following reaction takes
places in the leaves of the plant during photosynthesis:
Carbon dioxide + water + [in the presence of light energy] → Oxygen + glucose (or Carbohydrates)
The
products formed are glucose and oxygen. Carbohydrates, which are a form
of glucose, are synthesized from carbon dioxide and water. Glucose
is used by the plants for the growth. Some of the glucose is used
immediately and the extra glucose which is not used is stored in the
form of starch, in the leaves. Some amount of glucose is also stored in
the roots of the plants. The extra glucose is used to perform
photosynthesis when there is no sunlight.
Oxygen is given out
into the air through the stomata in the process of photosynthesis. The
oxygen that is released is used by human beings to breathe in during
their respiration process.
Ever wondered why this process is
called photosynthesis? The word photosynthesis is a combination of two
words: Photo and Synthesis. Photo means light in Greek and Synthesis
means putting together or combining. Hence, photosynthesis literally
means combining water and carbon dioxide in the presence of light.
So, the essential factors for photosynthesis to take place include:
• Sunlight
• Water
• Carbon dioxide
Underwater
photosynthesis takes place at a slower pace than the normal
photosynthesis. This is because energy from the sun is absorbed by the
water layers and only some amount of the energy reaches the plant.
There
are some plants which don't need the process of photosynthesis to grow.
Such plants include Mushroom, Venus flytrap etc. Mushroom gets the food
from the ground and its surrounding areas. Venus flytrap traps and
catches small insects which come near the leaves and eat them.
Human reproduction is sexual, with internal
fertilization and viviparous
development of the zygote and embryo.
The male
reproductive system
is formed of:
The penis:
a long cylindrical organ, covered in skin. Inside runs the urethra (a part of
both the reproductive system and the excretory system).
The testicles:
are the size of a nut. They produce sperm.
The scrotum:
The sack of skin that covers the testicles.
The vas
deferens: A tube that connects testicles to the urethra.
The glands:
prostate and seminalvesicles. They
produce liquids that mix with the sperm and form semen.
The female
reproductive system
is formed of:
The ovaries:
Two oval organs, the size of a nut. They produce ovules.
The fallopian
tubes: Two tubes that connect ovaries and uterus.
Uterus: An organ made of muscle. It shape and size is a
pear.
The vagina:
A tube that connect the female reproductive system to the exterior.
Vulva: Formed by folds of skin, called labia.
Fertilization isthe union of a sperm and a mature
ovule, which produces a zygote.
Pregnancy is the period when the zygote becomes the embryo, and
the embryo develops inside the mother’s uterus.
Childbirth is when the baby leaves the mother’s body.
Fertilization happens in the fallopian tube. The zygote
that forms becomes the embryo. This enters the uterus and
becomes joined to the wall. In this way the pregnancy starts.
Pregnancy lasts about nine months and is divided in three phases of three months each
one: first trimester, second trimester and third trimester.
When the baby is ready, the muscles of the wall of the
uterus produce contractions. The
amnion breaks and the baby comes out of the vagina.
The umbilical cord is cut. The remains of the cord
leave a scar on the abdomen of the baby: the
navel.
