Cells,tissues,organ systems,whole organisms

Question 1

How many characteristics of life are there? Name all.

Answer 1

Life manifests through seven fundamental characteristics, encompassing excretion, respiration, growth, movement, nutrient assimilation, irritability (commonly known as sensitivity), and the pivotal process of reproduction.

Question 2

Define Growth.

Answer 2

Growth refers to the gradual increase in an organism’s size, intricacy of cells.. This process unfolds through cellular activities like mitosis and differentiation, showcasing the organism’s ability to undergo developmental progression and maturation.

Question 3

Define Nutrition

Answer 3

Nutrition involves the intricate processes through which living organisms obtain and utilize essential substances, such as nutrients and energy, to sustain life.

Question 4

Define Respiration and the different types of respiration

Answer 4

Respiration refers to the intricate processes by which living organisms extract energy from nutrients, typically involving the exchange of gases like oxygen and carbon dioxide. This complex biological activity encompasses various types, including aerobic respiration, anaerobic respiration, and cellular respiration. Aerobic respiration occurs in the presence of oxygen, while anaerobic respiration takes place in its absence. Cellular respiration, a broader term, encompasses both aerobic and anaerobic processes, allowing cells to convert nutrients into energy to support essential life functions.”

Question 5

Define Irritability (sensitivity)

Answer 5

Irritability, also known as sensitivity, characterizes the capacity of living organisms to detect and respond to stimuli from their environment.

Question 6

Define Movement

Answer 6

movement denotes the purposeful alteration of an organism’s position or orientation.”

Question 7

Define

Answer 7

Excretion is the removal of waste and excess substances from an organism’s body to maintain internal balance and prevent harmful accumulations.”

Question 8

Define reproduction

Answer 8

“In biology, reproduction is the process by which organisms produce offspring, ensuring the continuation of their species. In asexual reproduction, organisms reproduce by using a form of
growth. They either divide into two (as happens with bacteria) or
they grow to produce part of the body that breaks away to form a new
individual.
Sexual reproduction involves the production of sex cells that fuse
together at fertilisation.

Question 9

What are all organisms made up of ?

Answer 9

All organisms are made of smaller units called cells

Question 10

Draw and label a plant cell

Answer 10

Nucleus,Chloroplast ,Chloroplas, Mitochondria Endoplasmic,reticulum,Vacuole, Cell Wall
(look at the textbook page 8)

Question 11

Draw and label a leaf cell

Answer 11

Nucleus,Endoplasmic,Golgi, Mitochondria, Reticulum,Apparatus, Cell Membrane, Chloroplasts, Vacuole,Cell Wall

Question 12

Some thing that plant and animal cells share in common.

Answer 12

Plant and animal cells exhibit numerous shared structural characteristics. They both possess a gel-like subtance called cytoplasm enclosed by a cell membrane that acts as a boundary between the cell and its environment. Within the cytoplasm, various cell structures are present.

Question 13

A next thing plants and animals has in common

Answer 13

One of the prominent structures in plant cells is the green chloroplasts. These specialized organelles exclusively exist in plant cells and play a crucial role in photosynthesis. Within chloroplasts, the pigment chlorophyll absorbs light energy. This absorbed energy becomes accessible to specific molecules within the chloroplast, facilitating the conversion of water and carbon dioxide into sugars and oxygen during the process of photosynthesis.

Question 14

A next thing in common

Answer 14

Easily observable with a light microscope in both animal and plant cells, mitochondria lack a light-absorbing pigment, making them less conspicuous compared to chloroplasts. Mitochondria are smaller in size and can be effectively visualized using a special dye during staining. Serving as the sites for aerobic respiration, mitochondria play a crucial role in releasing energy necessary for various cellular functions such as movement, growth, and division. Additionally, both animal and plant cells feature small, spherical vesicles known as vacuoles, which transport substances within the cell and are just visible under the microscope.

Question 15

An internal characterisic of cells

Answer 15

An internal characteristic of cells is the nucleus, which is delimited from the cytoplasm by the nuclear envelope. Within the nuclei are chromosomes, lengthy threads of DNA serving as the directives for cellular activities. Each DNA strand is partitioned into segments, with each segment functioning as a gene( Short length of DNA that controls a feature of an organism.)that regulates a specific attribute of the cell.

Question 16

Tell me about a plant cell

Answer 16

Plant cells maintain a consistent shape due to the presence of a rigid cell wall that surrounds them. Positioned outside the cell membrane, the cell wall is composed of layers of cellulose fibers. Additionally, plant cells possess a sizable, enduring vacuole filled with aqueous sap containing dissolved salts and sugars. This vacuole serves as a storage compartment for the cell. The outward force exerted by water in the vacuole against the cell wall provides structural support. Consequently, the cell wall withstands internal water pressure, preserving the cell’s shape.Within leaves, there are two cellular layers containing chloroplasts. The upper layer comprises elongated, cylindrical cells, while the lower layer consists of cells with a more spherical shape.

Question 17

Tell me the cell structure and functions

Answer 17

^Cell surface membrane- Controls which substances enter and leave the cell
^Endoplasmic reticulum -Many interconnected tubes and canals that transport substances around the cell; if there are ribosomes
attached to it, it is known as rough endoplasmic reticulum
^Golgi apparatus (Golgi body) -Packages substances produced by endoplasmic reticulum for export out of the cell
^Lysosome Contains- chemicals that can destroy cells which are eaten by the cell and any worn out cell structures such
as mitochondria
^Mitochondrion (plural: mitochondria)- All the chemical reactions of aerobic respiration occur within this structure
^Nuclear envelope- Separates the nucleus from the cytoplasm; small pores (holes) in the nucleus allow substances to pass
between the nucleus and the cytoplasm
Nucleolus Produces ribosomes
^Nucleus Contains DNA that makes up the chromosomes which control the cell’s activities
^Ribosome -Very small structures that make proteins from amino acids
^Vesicles (small vacuoles) -Small spherical structures that carry substances packaged by the Golgi apparatus to the cell surface membrane to be exporte

Question 18

Tell me about Microbes

Answer 18

Bacteria, viruses, and fungi fall under the category of microbes or microorganisms. Unlike bacteria and fungi, viruses are not considered living organisms. Several species of bacteria and fungi play a crucial role in decomposing deceased and decaying matter and are referred to as decomposers. Certain types of bacteria and fungi are employed in the production of food items like yogurt, bread, cheese, and wine. Viruses have found application in genetic engineering. Pathogens are organisms that infect others and induce diseases, with many of them being microbes.

Question 19

Tell me about bacteria

Answer 19

Bacteria exhibit a straightforward cell structure, as depicted in. They vary in shape, with some being spherical and others rod-shaped, often forming short chains. Bacteria are typically only a few micrometers in length and are observable using light and electron microscopes.

The bacterial cells are enveloped by cell walls, distinct from plant cell walls as they lack cellulose. However, these bacterial cell walls serve the same purpose of maintaining the cell’s shape and preventing it from rupturing. In certain bacterial species, cells are enclosed by a protective slime capsule, offering defense against other organisms and diminishing the risk of desiccation.

Decomposer An organism that
feeds on and breaks down dead
bodies and wastes.
Pathogen An organism that
causes disease.

Question 20

Draw and label a bacteria cell

Answer 20

Capsule-Protective outer layer, Cell Wall-Structural support and protection,
Cell membrane-Selectively regulates what enters and exits the cell. Membrane Cytoplasm-Gel-like substance, where cellular activities occur,(DNA)Nucleoid- Region containing genetic material (DNA),Ribosomes-Site of protein synthesis ,Flagellum-Whip-like structure for cell movement.

Question 21

A little fact on bacteria

Answer 21

Bacteria have no nucleus, just a loop of DNA within the cytoplasm. The
structure of bacteria differs from animal and plant cells, as they do not have
chloroplasts or mitochondria. Some bacteria have whip-like extensions
called fagella for moving through water or other fuids.
Bacteria are found everywhere – in the air, in water and in the soil. Under
good conditions, bacteria may divide every twenty minutes, so it does not
take long to have a very large number of bacteria that you can see on agar as
a colony. Each colony starts from just one cell.