Biology Class: Visible Structures & Unicellular Organisms

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Questions and Answers

What function do the visible structures of organisms serve?

They help organisms move faster.

They supply cells with oxygen, water, and nutrients. (correct)

They protect organisms from predators.

They enhance the aesthetic appearance of organisms.

Which of the following statements about unicellular organisms is true?

They are made of a single cell. (correct)

They can only live in extreme conditions.

They reproduce by forming multicellular clusters.

They are always harmful to the environment.

How do phytoplankton contribute to the ecosystem?

They decompose organic matter in terrestrial environments.

They produce a majority of the Earth's oxygen. (correct)

They solely rely on multicellular organisms for survival.

They consume all available nitrogen.

What role do decomposers play in the environment?

They turn compost into nutrients and usable nitrogen. Signup and view all the answers

What happens when a bacteriophage injects its DNA into a bacterium?

The bacteriophage reproduces until the bacterial cell bursts. Signup and view all the answers

Where can unicellular organisms typically be found?

In soil, water, and on multicellular organisms. Signup and view all the answers

What is a primary characteristic of unicellular organisms compared to multicellular organisms?

They can perform complex functions independently. Signup and view all the answers

What is a significant benefit of microbes, specifically phytoplankton, in the food chain?

They capture sunlight and produce food for larger organisms. Signup and view all the answers

What is the primary function of skeletal muscle cells?

To contract and make joints move Signup and view all the answers

Which type of muscle is responsible for pumping blood throughout the body?

Cardiac muscle Signup and view all the answers

What cellular structure is primarily involved in photosynthesis within leaf cells?

Chloroplasts Signup and view all the answers

What is the main product of cellular respiration?

Water and carbon dioxide Signup and view all the answers

During which phase of mitosis do chromosomes align in the center of the cell?

Metaphase Signup and view all the answers

Which type of plant cell is primarily responsible for absorbing water and nutrients from the soil?

Root cells Signup and view all the answers

How many pairs of sex chromosomes do humans possess?

1 Signup and view all the answers

What does the term 'cytokinesis' refer to during cell division?

Separation of the cytoplasm Signup and view all the answers

Which component of DNA carries genetic information?

Nitrogenous bases Signup and view all the answers

What is the result of an extra copy of chromosome 21 in humans?

Down syndrome Signup and view all the answers

What is the primary function of red blood cells?

Carry oxygen from the lungs to the body Signup and view all the answers

Which structure do E.coli bacteria use for movement?

Flagellum Signup and view all the answers

How do amoebas capture their prey?

Through shapeshifting and engulfing Signup and view all the answers

What type of organisms are bacteriophages specifically designed to target?

Bacteria Signup and view all the answers

Which of the following is not a characteristic of red blood cells?

Contain a nucleus Signup and view all the answers

What defines specialized cells in multicellular organisms compared to unicellular organisms?

They carry out specific tasks Signup and view all the answers

Which of the following cells is primarily involved in nutrient absorption in the intestines?

Villi Signup and view all the answers

What is a common feature of all multicellular organisms?

Depend on specialized cells for function Signup and view all the answers

Why are unicellular organisms generally micro-sized?

To enhance diffusion and osmosis efficiency Signup and view all the answers

What role do contractile vacuoles play in amoebas?

Expel excess water Signup and view all the answers

Which cell is responsible for transmitting electrical impulses in the nervous system?

Nerve cells Signup and view all the answers

What is a key characteristic of superbugs?

Immune to antibiotics Signup and view all the answers

In a frog, which cells are primarily responsible for capturing insects?

Muscle cells Signup and view all the answers

Which of the following cells stores energy?

Fat cells Signup and view all the answers

Study Notes

Visible Structures and Their Function

Organisms' visible structures (e.g., jaws, teeth, eyes, leaves) work together to acquire the water, oxygen, and nutrients cells need.
These structures enable organisms to obtain necessities from their environment.
The internal processes for acquiring resources occur without conscious awareness.

Unicellular Organisms

Unicellular organisms are composed of a single cell.
They are typically smaller than a speck of dust and live in diverse environments (e.g., water, soil, other organisms).
Some are harmful, while others are crucial for life on Earth (e.g., phytoplankton).
Phytoplankton conduct photosynthesis, produce atmospheric oxygen, and are the base of the ocean food chain.
Phytoplankton also contribute to matter cycling and global food resources.
Decomposers (e.g., fungi, protozoa, bacteria) break down dead matter and return nutrients and nitrogen to the environment.
Bacteriophages, unlike unicellular organisms, are viruses consisting of DNA within a protein coat and need a host cell to replicate.

Movement of Unicellular Organisms

Unicellular organisms move using diverse methods.
- Paramecia use cilia (hair-like structures) like oars to propel themselves.
- E. coli bacteria rotate a flagellum (tail-like structure) to "swim".
- Amoebas alter their shape, using pseudopods (cytoplasmic extensions) to move and capture prey.

Amoeba Characteristics

Amoebas inhabit various environments, mostly water, but also decaying materials or inside other organisms.
Possess a semipermeable membrane, nuclei, cytoplasm, food vacuoles, and contractile vacuoles.
They obtain nutrients (carnivores, herbivores, or omnivores) by consuming algae, bacteria, and small organisms.

Multicellular Organisms and Specialized Cells

Multicellular organisms employ specialized cells for specific functions.
Smaller cells facilitate efficient diffusion and osmosis.
Oxygen diffuses 0.01 mm in a fraction of a second but takes 100 times longer to diffuse 1 mm.
Cell size affects the efficiency of cellular processes like diffusion and osmosis.
Multicellular organisms have a wide array of specialized cells (e.g., skin, bone, muscle).

Specialized Animal Cells

Red blood cells: Carry oxygen throughout the body.
White blood cells: Defend the body against pathogens.
Intestinal lining cells: Absorb water.
Villi: Absorb digested food and water in the small intestine.
Fat cells: Store energy.
Nerve cells (neurons): Transmit electrical impulses.
Brain cells (neurons): Receive/transmit electrical impulses.
Bone cells: Provide support and store essential nutrients.
Muscle cells: Enable movement (skeletal, smooth, cardiac).
Ciliated cells: Move fluids and particles (e.g., in airways, fallopian tubes).
Skin cells: Protect the body from harm.

Specialized Plant Cells

Plants have shoot and root systems comprised of specialized cells.
Leaf cells: Conduct photosynthesis converting sunlight into energy.
Stem cells: Transport water and materials throughout the plant.
Root cells: Absorb water and nutrients from the soil.

Cellular Processes

Cellular respiration: Mitochondria convert oxygen and glucose into energy.
Photosynthesis: Chloroplasts convert sunlight, water, and carbon dioxide into glucose and oxygen.
Cell division (mitosis): Cells duplicate and split into two daughter cells with identical genetic material. (Detailed mitosis phases are included)
DNA (deoxyribonucleic acid): Contains genetic information passed from generation to generation; composed of four bases (A, C, G, T).
Chromosomes: Structures carrying genetic information; humans have 46 chromosomes.

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Description

This quiz covers the visible structures of organisms and their function in acquiring nutrients and resources. It also explores unicellular organisms, their environments, and their roles in ecosystems, including phytoplankton and decomposers.