A2.2.9 - Atypical Cell Structures

name four types of atypical cells and their unique features

• Aseptate fungal hyphae: Fungal cells with continuous cytoplasm + multinucleated

• Skeletal muscle fibers: Mutlinucleated syncytium

• Red blood cells:  Enucleated cells

• Phloem sieve tube elements: Plant cells lacking a nucleus but supported by companion cells

how are aseptate fungal hypnae different from typical fungi?

their thread-like structures called hypnae aren’t divided by septa (walls) → aseptate hypnae + continuous cytoplasmic network called coenocyte

advantages of the absence of septa in aseptate hypnae

• unrestricted cytoplasmic flow → faster growth

• efficient nutrient distribution

• rapid response to environment

what is a common example of aseptate hyphae?

bread molds

coenocyte

a continuous cytoplasmic network with multiple nuclei

found in aseptate fungal hyphae

3 benefits of multinucleation in skeletal muscle fibers

• Efficient protein synthesis to support muscle contraction

• Localized control of cellular functions

• Enhanced ability to repair and regenerate

syncytium

a multinucleated cell formed by the fusion of indiv. cells

edx. skeletal muscle fibers

3 adaptations of RBC

• no nucleus → More space for hemoglobin

• Increased flexibility → squeezing through capillaries

• Biconcave shape → surface area

3 tradeoffs of a lack of nucleus in RBC

• limited lifespan (120 days)

• X repair or reproduction

• reliance on pre-synthesized proteins

why do RBC have no nucleus?

increase space for haemoglobin → carry more oxygen

what are phloem sleeve tubes responsible for?

transporting sugars

unique features of phloem sleeve tubes

• Lack of nucleus and most organelles

• Presence of sieve plates with pores

• Close association with companion cells

what do companion cells do?

• metabolic support

• facilitate loading and unloading of sugars

• maintain cellular func.s