A2.2.9 Atypical cell structure in eukaryotes | Quizlet

What is the benefit of aseptate hyphae in fungi?

Aseptate hyphae allow cell contents to flow freely, optimizing nutrient distribution and growth.

Define coenocyte.

A coenocyte is a continuous cytoplasmic network formed by aseptate hyphae.

Why do red blood cells (RBCs) lose their nucleus?

RBCs eject their nucleus during development to create more space for hemoglobin, the oxygen-binding protein.

What is the trade-off of enucleated red blood cells?

While they can carry more oxygen, they cannot repair themselves, limiting their lifespan to 100-120 days.

Are enucleated red blood cells dead?

No, they are metabolically active and capable of transporting oxygen.

What is the function of companion cells in the phloem?

Companion cells handle the energy and metabolic needs of sieve tube elements, ensuring they remain functional.

Why are sieve tube elements lacking a nucleus advantageous?

Their streamlined structure without a nucleus allows for efficient sugar transport, as they rely on companion cells for metabolic support.

What is a syncytium?

A syncytium is a structure formed by the fusion of multiple cells, resulting in a single cell with multiple nuclei.

Why do skeletal muscle fibers have multiple nuclei?

Multiple nuclei allow for better control of growth, repair, and protein production in the extensive cytoplasm of the muscle fiber.

What are the four exceptions to the cell theory?

Aseptate fungal hyphae

Skeletal muscle fibers

Red blood cells

Phloem sieve tube elements.

What is the lifespan of a red blood cell?

100-120 days.

How do sieve tube elements and companion cells work together?

Sieve tube elements are streamlined for sugar flow, while companion cells manage their metabolic needs.

What is the common thread among atypical cell structures?

They all demonstrate adaptations that enhance efficiency for specific functions.

Why are nuclei important for muscle cells?

Each nucleus controls part of the muscle fiber, facilitating growth, repair, and protein production.

What is the shape of red blood cells and why is it beneficial?

Biconcave shape, which increases their surface area-to-volume ratio for oxygen transport.

List one way fungi benefit from aseptate hyphae.

Fungi can quickly respond to environmental changes by reallocating resources across the hypha.

What are hyphae?

Thread-like structures that fungi use to grow.

What happens to red blood cells after their lifespan?

They cannot repair themselves due to the absence of a nucleus, leading to their eventual degradation.

Why is the term 'sieve tube element' used instead of 'cell'?

Because sieve tube elements lack many features typically associated with cells, such as a nucleus.