BIOLOGY 1 Marks Question

Motor cells.

Tracheid.

The main function of phloem parenchyma is food storage. It also helps in translocation of food.

Collenchyma, it is present only at corners of cells.

Phellem (cork)-phellogen (cork cambium)-phelloderm (secondary cortex).

Fruit is a mature ovary which is developed after fertilization.

Pericycle is made of sclerenchyma cells and occurs in the form of semilunar patches above the phloem and inner to the endodermis.

In alternate phyllotaxy just one leaf grows from one node, while in opposite phyllotaxy two leaves grow from a single node.

Bulliform cells present in the upper epidermis of monocot leaves make the leaves curl in plants during water stress.

The age of a tree is calculated by counting the number of annual rings; an annual ring refers to the wood produced during a year and includes the spring wood and autumn wood.

Stele refers to all the tissues that are found inner to the endodermis and consists of pericycle, vascular bundles, conjuctive tissue and pith.

In valvate aestivation sepals or petals don't overlap, while in twisted aestivation sepals or petals slightly overlap.

Collenchyma.

Sieve tube It is present in the phloem tissue. It's function is the transportation of synthesized food throughout the plant.

1. Pericycle is formed of parenchymatous cells.
2. It gives rise to lateral roots.

• The size of vascular bundles is dependent on the thickness of veins.
• The veins vary in thickness in the reticulate venation of dicot/ dorsiventral leaves and hence the difference in size.

1. Phellogen: is meristematic and divides to produce new cells.
2. Phelloderm: stores food materials.

The presence of root cap makes the root's apical meristem subterminal.

1. Roots show radial vascular bundle.
2. Monocot roots show polyarch xylem.
3. Dicotyledonous stems and mono-cotyledonous roots show well developed pith.

Tap roots, by going deeper inside the ground, provide better anchorage. So, plants can be very big in size.

Exarch.

Companion cells are connected to the sieve tube elements by the pit fields present in the common longitudinal walls between them.

Meristematic tissue.

Bark means cork, cork cambium, secondary cortex and secondary phloem. Debarking removes all these tissues.

Lenticels are the lens-shaped openings in the bark of dicot stems.

Root cap protects the tender apex.

Morphology is the study of the form, structure and configuration of an organism.

Root apical meristem-Root tip. Shoot apical meristem-Topmost regions of stem axis.

1. Monocot plants.
2. Gymnosperms.

Plant anatomy is the branch of science that studies the internal structure of plants.

• Cuticle is the waxy substance present on the outer surface of epidermis of leaves and stem.
• It prevents the loss of water through transpiration.

Palisade and spongy parenchyma are the two tissues related to mesophyll.

Bast fibres; they are sclerenchyma fibres.

Growth occurs in the meristems.

It develops from part of pleurome or procambium.

Isobilateral (equifacial) leaves are placed in a plant in such a way that both its surfaces receive equal amount of sunlight. It does not have distinct upper and lower surfaces. Mesophyll is usually indistinguishable. Most of the monocot plants have isobilateral leaves.

The pith consists of a large number of rounded, parenchymatous cells with big intercellular spaces. It occupies the central portion of the stem it.

Androecium is composed of stamens. Each stamen which represents the male reproductive organ consists of a stalk or a filament and an anther. Each anther is usually bilobed and each lobe has two chambers, the pollen-sacs. The pollen grains are produced in pollen-sacs.

1. Upper surface is covered by adaxial epidermis.
2. Lower surface is covered by abaxial epidermis.

Stem and leaves.

• Bulliform Cells are certain adaxial epidermal cells along the veins, which have become large, empty and colourless.
• When bulliform cells are turgid, the leaf surface is exposed; when they are flaccid, the leaves curl inwards and the surface is not exposed.

Phellen → Phellgen → Phelloderm.

Apical meristems are responsible for the growth in length of roots and shoot.

Phellogen, phellem and phelloderm are collectively called periderm. ​​​​​​

1. Two to four groups of vascular tissues.
2. Small or inconspicuous pith.

Due to the continued formation and accumulation of a large quantity of secondary xylem, the thin-walled phloem cells get crushed.

If protoxylem lies next to the phloem, this arrangement of xylem is called exarch.

The endodermis of a dicot stem is rich in starch grains, so it is called starch sheath.

These are the narrow bands of parenchyma which pass through the secondary xylem and secondary phloem in the radial direction formed by the cambial ring during secondary growth.

Phloem fibres/ bast fibres/ sclerenchyma fibres.

Epiblema.

Fascicular cambium, interfascicular cambium, cork cambium/ phellogen.

Cuticle and cutinised outer walls of epidermal cells reduce the rate of water loss through transpiration.

A is lumen.

The stomata are more in number in the lower epidermis than the upper epidermis.

1. Collenchyma.
2. Parenchyma.

No, lenticels are mostly found in woody trees.

Potato, Ginger, Turmeric, Zimicand.

1. The companion cells help to regulate the pressure gradient in sieve tubes.
2. In the absence of a nucleus, the functions of sieve tubes are regulated by the nucleus of the ompanion cells.

Arrangement of flowers on the floral axis is called inflorescence.

Amphibasal.

They are considered as primary meristems because they appear early in the life of a plant and contribute to the formation of primary plant body.

Mature or permanent cells are those cells which have become structurally and functionally specialised and lost the capacity to divide.

Casparian strips are the bands of deposition of suberin on the tangential and radial walls of the endodermal cells of the roots.

1. The bark formed early in the growing season (spring), is called early bark.
2. The bark formed late in the growing season (autumn), is called late bark.

The structures that get entangled in the teeth while eating fruits like peach and pear are actually the stone cells or brachysclereids which areunbranched, short and isodiametric type of sclereids. These stone cells usually occur in groups and provide grit or stone like hardness that get entangled in the spaces between teeth.

Epidermis, Cortex, Endodermis, Pericycle, Pith.

Pericycle and companion cells of phloem.

The xylem vessels are formed from a number of cells, so they are called syncytes.

When there are more than six xylem groups in the radial vascular bundles of roots, it is called polyarch xylem.

Apical meristems are located at the tips of root and shoot.

Xylem parenchyma.

Guard cells possess chloroplasts and carry out photosynthesis, while other epidermal cells have no chloroplasts.

In three major zones, i.e., cortex, pericycle and pith with Smedullary rays.

In plants, stele is constituted by all the tissues that are on the inner side of the endodermis, i.e., pericycle, vascular bundles and pith.

The dark colour is due to the accumulation of secondary metabolites like tannins, gums, oils and resins, etc., in the wood tissue.

By plasmodesmata or cytoplasmic bridges.

In monocots there is no cambium and the vascular bundles are scattered; hence, there is no secondary growth.

Edible part in mango: Mesocarp. Edible part in coconut: Seed.

The number and position of auxillary bud is an indicator if a leaf is a simple one or a compound one. In neem leaves there is a single auxillary bud at the start of the bunch of leaflets. So it is a compound leaf.

Companion cells are associated with sieve tubes in angiosperms. They help sieve tubes in the translocation of solutes.

Diadelphous.

Secondary xylem.

Xylem parenchyma.

Casparian strips or casparian bands.

Modification of leaf.

Endodermis.

Phloem.

Thick waxy layer called cuticle is present on the surface of the leaves which helps the plant to prevent loss of water. It is absent in roots.

The cambium lies parallel to the circumference and helps to increase in girth, hence is called as lateral meristem.

Heartwood is durable due to the deposits of substances like resins, tannins, oils, gums, etc, which make the wood hard and resistant to the attacks of microbes and insects.

Secondary growth in dicot stems is achieved by the activity of fascicular, inter fascicular cork cambium and the lateral meristems.

Parenchymatous tissue stores starch (food) in potato and sclerenchymatous tissues make the shells of the nuts.

As the dicot stem continues to increase in girth (diameter) due to the activity of vascular cambium, the epidermis and the peripheral layers of cortex become broken; hence there is a need to provide new protective cell layers.

The bulliform cells present in the epidermis of grasses help in folding of leaves during hot summer day and prevent transpiration.

The food gets stored in specialized parenchymatous cells present either in roots or stems.

In dicot stems, hypodermis consists of a few layers of collenchyma cells, whereas, in case of monocot stems, hypodermis consists of 2-3 layers of sclerenchyma cells.

The shoot apical meristem changes into floral meristem. This finally results in development of flower. Internodes do not elongate and the axis gets condensed. Nodes, in stead of producing leaves, produce different floral parts.

Phyllotaxy is the arrangement of leaves on the branch.

In grasses, certain adaxial epidermal cells along the veins modify themselves into large, empty, colourless cells. These are called bulliform cells or motor cells. Bulliform cells help in folding and unfolding of grass leaves. When the bulliform cells in the leaves have absorbed water and are turgid, the leaf surface is exposed. When they are flaccid due to water stress, they make the leaves curl inwards (inrolling) to minimise water loss (transpiration).

The ray parenchyma cells help in radial conduction of water.

Pericyle.

In banana, the lateral branches originate from the basal and underground portion of the main stem, grow horizontally beneath the soil and then come out obliquely Som upward giving rise to leafy shoots.

Collateral vascular bundles.

Ring of vascular cambium (cambial ring) is formed by two types of meristems, fascicular or intrafascicular and interfascicular cambium. Intrafascicular cambium is a primary meristem which occurs as strips in vascular bundles. Interfascicular cambium is a secondary meristem which arises from the cells of medullary rays which occur at the level of intrafascicular strips. The two types of meristematic tissues get connected to form a cambial ring.

Mesophyll is the ground tissue of leaves; it consists of thin-walled, chloroplast-containing cells.

Veins and veinlets are like supply channels in leaves. They transport water to leaves and take back products of photosynthesis to different parts of plants.

During the formation of leaves and elongation of stem, some cells of the shoot apical meristem that are left behind, constitute the axillary buds.

Meristems are the specialised regions of active cell divisions in plants.

These cells are called bulliform cells.

The vessel members are interconnected through perforations in their end/ common walls.

The parenchymatous tissue present between xylem and phloem of roots, is called conjuctive tissue.

Fascicular combium and phellogen (cork cambium).

It is completely secondary in origin because it originates from the tissue located below the phloem groups and from pericycle cells that lie opposite to the xylem groups of the vascular bundles.

1. Vascular bundle consists of xylem and phloem which conduct water and food, respectively.
2. As a science student Arun showed willingness to know reasons and significamce of each statement.

The racemose inflorescence shows unlimited growth. The apex in this type of inflorescence does not terminate into a flower and continues to grow. Flowers are borne laterally in racemose.

Fabaceae.

The presence of nodes and internodes on ginger gives a clue that it is not a root, but a stem.

In fibrous roots there are more direct channels to stem for water absorption. So, fibrous roots don't have to go deep inside the ground in search of water.

When stamens are attached to the perianth, it is called epiphyllous arrangement.

Pulp of the guava and pear.

1. Xylem functions as the conducting tissue for water and minerals.
2. It also provides mechanical strength to plant parts.

The vessel members are interconnected through perforations in their common end walls.

3. palisade parenchyma.

The size of the vascular bundles is dependent on the size of veins present in leaves.

1. When the protoxylem lies towards the centre/ pith and the metaxylem lies towards the periphery of the organ, the arrangement of xylem is endarch.
2. It is found in stems.