Eukaryotic Cell Diversity Flashcards
(40 cards)
What is a protist?
A large and diverse group of eukaryotic micro-organisms. Most are single celled but a small number are multi-cellular.
What is the main difference between eukaryotes & prokaryotes?
The presence of organelles & DNA enclosed in a nucleus.
Suggest a problem for single-celled organisms which are very large.
The absorption of sufficient nutrients & the excretion of wastes. This is due to the volume to surface area ratio.
Another problem is transport & communication between distant cell areas.
List two ways in which large single-celled organisms can combat problems relating to their size regarding nutrients & waste.
Many Protists have evolved a flattened, lobed shape to increase surface area.
Many have also evolved the ability to engulf food, such as the amoeba.
What is the process by which single-celled organisms engulf food called?
Endocytosis.
Explain the process of endocytosis.
A flexible cell surface & the ability to extend lobes of cytoplasm known as pseudopods a.
What strategy to large unicellular Protists have to address the problem of communication within the cell?
Extra large nuclei or more than one nucleus to reduce distance between the nucleus and other parts of the cell.
Name an advantage of colony formation
Colonies are larger in size than individual organisms, which may reduce predation by filter feeders.
What are chlorophyta?
Photosynthetic eukaryotes, some of which are unicellular, some colony-forming and others multicellular.
They are a division of the eukaryotic green algae.
What is the difference between colonies and multicellular organisms?
Colonies contain identical individuals.
What is volvox? Does it count as a colony or a multicellular organism?
It is a very simple multicellular organism because it contains differentiated cells. Several thousand cells can be present, some of which are somatic. Others are reproductive & can lead to the formation of a new colony.
List some of the features of fungi.
The majority of fungi consist of microscopic filaments called hyphae, which grow at their tips and branch repeatedly.
A mass of hyphae is called mycelium.
Hyphae have rigid cell walls.
Are fungi multicellular or unicellular? Why are they difficult to classify?
They are generally considered to be multicellular. It is difficult to classify them because they can be made up of divisions in the hyphae to make cell-like compartments, or have no divisions and multiple nuclei in each hypha.
Are there single-celled fungi?
Yes, many spend part or all of their life cycle in single-celled or yeast form.
What are the three main tissue types in flowering plants?
Ground tissue, vascular tissue & dermal tissue.
Define plant.
Multicellular eukaryotes which photosynthesise, they evolved from green algae. They are non motile with rigid cell walls.
Describe plant ground tissue.
It provides packing and support and energy storage.
What is a palisade cell and where is it found?
Photosynthetic cells found in the ground tissue of plants.
What are parenchyma cells?
The basic structural element of plants which form the majority of stems, roots & leaves.
What is a plasmodesmata?
Small pores linking the cells of plants. They are lined by a plasma membrane and have a strand of cytoplasm in the middle.
Name & briefly describe the two types of vascular tissue in plants.
Xylem: transports water and dissolved ions from the roots around the rest of the plant.
Phloem: transports the produce of photosynthesis around the plant.
What is plant dermal tissue?
Epidermis of a plant, it covers the entire plant. It is usually a single cell thick.
In shoots it has a cuticle.
What are stomata?
Pores in the epidermis of leaves. They open & close to facilitate the gas exchange needed for photosynthesis.
List the principle types of animal cells.
Epithelial cells Endocrine cells Muscle cells Neurones Connective tissue Adipocytes Blood cells Immune system cells Germ cells
