Domain 2 : Life Science

Question 1

Plants (five groups)

Answer 1

Primitive groups: algae, fungi - lack true roots, stems, and leaves. Algae range from a single cell to huge seaweed; mostly they inhabit lakes and oceans. Fungi include molds, yeasts, and mushrooms. Fungi lack chlorophyll and thus are incapable of manufacturing food, so they are either parasites, preying on other living organisms.

Ferns - lack seeds and reproduce by means of spores, each of which may develop into a new plant without fertilization.

Gymnosperms - cone-bearing plants (including pines) with seeds exposed on cone scales.

Angiosperms - flowering plants that bear their seeds within fruits.

Question 2

Photosynthesis

Answer 2

a metabolic pathway that converts light energy into chemical energy. Plants use the energy in sunlight to convert carbon dioxide from the atmosphere, plus water, into simple sugars. These sugars are then used as building blocks and form the main structural component of the plant. Chlorophyll is generally present in plant leaves and often in other plant parts as well. Equation: 6co2+6h2o+light–>c6h206+6o2

Question 3

Cell

Answer 3

the smallest amount of living matter, a bit of organic material that is the unit of structure and function for all organisms.

Question 4

nucleus

Answer 4

a membrane-enclosed organelle found in all eukaryotic cells. It contains most of a cell’s genetic material, organized as multiple long and linear DNA molecules in complex with a large variety of preens, such as histones, to form chromosomes. Function is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression.

Question 5

Chloroplasts

Answer 5

organelles found in plant cells and eukaryotic algae that conduce photosynthesis. Chloroplasts absorb light and use it in conjunction with water and carbon dioxide to produce sugars, the raw material for energy and biomass production in all green plants and the animals that depend on them, directly or indirectly for food. they capture light, and are members of a class of organelles known as plastids.

Question 6

Mitochondrion

Answer 6

a membrane-enclosed organelle founding most eukaryotic cells. Sometimes described as cellular power plants because they generate most of the cell’s supply of ATP, use as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, and cell death, as well as the control of the cell cycle and cell growth.

Question 7

Digestion System

Answer 7

The breaking down of chemicals in the body into a form that can be absorbed. It is also the process by which the body breaks down chemicals into smaller components that can be absorbed by the blood stream.

Question 8

Circulatory System

Answer 8

an organ system that moves nutrients, gasses and wastes to and from cells, helps fight diseases, and stabilizes body temperature and pH to maintain homeostasis. Main components are the heart, blood, and blood vessels.

Question 9

Sensory System

Answer 9

includes those specialized structures that initiate a nerve impulse after being affected by the environment. The eyes are the organs of vision. Light rays are refracted as they pass through the cornea, lens, and vitreous body to focus on the retina, where an image is formed. The optic nerve then carries impulses from the light-sensative cells of the retina to the brain.

Question 10

The nervous system

Answer 10

is composed of the brain, spinal cord, and peripheral nerves that extend throughout the body. The functional unit of the nervous system is the neuron, a nerve cell with short dendrites that carry electrical impulses to the cell body, and a long axon, the outgo in g fiber along which the impulse is transmitted further.

Question 11

Organisms

Answer 11

Complex chemical systems, organized in ways that promote reproduction and some measure of sustainability or survival. It is generally the phenomena of entire organisms that determine their fitness to an environment and therefore the survivability of their DNA-based genes.

Question 12

Adaptation

Answer 12

Characteristic of an organism that has been favored by natural selection and increases the fitness of its possessor. Adaptation is the change in living organisms that allows them to live successfully in an environment. Adaptations enable living organisms to cope with environmental stresses and pressures. Can be structural, behavioral, or physiological.

Question 13

Ecosystem relationships

Answer 13

primarily governed by stochastic (chance) events, the reactions these events provoke on non-living material, and the responses by organisms to the conditions surrounding them. Thus, an ecosystem results from the sum of individual responses of organisms to stimuli from elements in the environment. The presence or absence of populations merely depends on reproductive and dispersal success, and population levels fluctuate in response to stochastic events.

Question 14

Food chains

Answer 14

describe the eating relationships between species within an ecosystem. Organisms are connected to the organisms they consume by lines representing the direction of organism or energy transfer. Food chains also show how the energy from the producer is given to the consumer.

Question 15

Food Webs

Answer 15

interconnected energy systems. Demonstrates the alternate energy links available to an organism. Explain predator/prey relationships in an ecosystem and include networks of food chains.

Question 16

Food Pyramids

Answer 16

illustrate energy flow in an ecosystem. The base of the pyramid (producers) supports all of the other keels of the pyramid. At each succeeding level of the pyramid, there is a decrease in available energy.

Question 17

Metamorphosis

Answer 17

a distant change in physical appearance an organism can go through between birth and adulthood.

Question 18

Life cycle of a frog

Answer 18

1. the life cycle of a frog starts with an egg. A female frog generally lays thousands of eggs in water. The eggs are highly vulnerable to predators, and so frogs have evolved many techniques to ensure the survival of their next generation.
2. The eggs hatch and life continues as tadpoles. They lack lungs, eyelids, and front and hind legs. Tadpoles are typically herbivorous, feeding mostly on algae.
3. then, frogs undergo metamorphosis and they transition into adult form. Metaorphasis involves a dramatic transformation of morphology and physiology, as tadpoles develop hind legs, then front legs, lose their gills, and develop lungs.
4. After metamorphosis, young adults may leave the water and disperse into terrestrial habitats, or continue to live in the aquatic habitat as adults.

Question 19

The butterfly life cycle

Answer 19

1. Egg stage: the eggs are usually laid on plants; this stage lasts a few weeks for most butterflies.
2. Larva, known as a caterpillar, or feeding stage: From the eggs, butterfly large, or caterpillars, consume plant leaves and spend practically all of their time in search of food. When the larva is fully grown, hormones are reduced.
3. Pupa or cocoon stage: the larva transforms into a pupa by anchoring itself to a substrate and molting the lat time.
4. Adult butterfly stage: The adult, sexually mature, stage of the insect is known as the imago. After it emerges from its pupa stage, a butterfly cannot fly until the wings are unfolded.

Question 20

Asexual reproduction

Answer 20

A form of reproduction which does not involve meiosis or fertilization. Only one percent is involved in asexual reproduction. It’s the primary form of reproduction for single-celled organisms such as the archaea, bacteria, and protists.

Question 21

Meiosis

Answer 21

a process of reductional division in which the number of chromosomes per cell is cut in half. In animals, meiosis always results in the formation of gametes, while in other organisms it can give rise to spores. Meiosis is essential for sexual reproduction and therefore occurs in all eukaryotes (animals, plants, fungi, and protists are eukaryotes) that reproduce sexually. Doesn’t occur in archaea or bacteria, which reproduce through asexual processes such as binary fission.

Question 22

Mitosis

Answer 22

cell division of the parent cell’s genome into two daughter cells. includes: interphase, prophase, metaphase, anaphase, and telophase.

Question 23

Natural selection

Answer 23

is the process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common.