Theme B: B2 Cells - B2.3 Cell Specialisation Flashcards

Question

sperm cell size importance

Answer 1

sperm cells are relatively small because they only carry out the function of transporting genetic material so VIABLE ZYGOTE can be formed.

Answer 2

1) contain haemoglobin that combine with and release oxygen 2) biconcave disk shape allowing more surface area for oxygen absorption 3) lack mitcohondria and nucleus 4) flexible and limited size because they need to move through narrow blood capillaries

Answer 3

* **bigger than red blood cell** * main function is **defense against infections** * retain **nucleus** throughout lifetime * several distinct types and each have a specific function * many possess **vesciles with enzymes** that can kill microorganisms. the enzymes are also used to break down harmful cellular debris brought in by phagocytosis * their size is increased due to necessary presence of **nucleus**, **granules**, and **organelles like mitochondria**

Answer 4

there are several types of neurons, the distinct types exhibit adaptations for specialised roles e.g. motor neruons carry impulses from brain or spinal cord that allow muscles to appropriately respond to stimuli: * this neuron type has long fires called axons that can carry impulses up and down body over long distances * the axon of motot neurons can extent up to 1 meter in human body * this allows efficient and rapid transmission of nerve impulses from brain and spinal cord to muscles in limbs to produce movement

Answer 5

skeletal muslce fibres are specialised cells found in skeletal muscle: * the fibres are cylindrical and surrounded by membranes capable of impulse propagation * skeletal muslce fibres can be up to 12 cm long and longer than muscle fibres in smooth muscle or cardiac muscle * this muscle type can only produce movement by contraction. becaus ethe fibre is relatively long, all the units contracting together produce a significant movement in short: * a long, cylindrical shape * a membrane capable of impulse propagation * multiple nuclei (multinucleated) * visible bands capable of shortening to produce voluntary movement.

Answer 6

1) Basic processes of cell physiology, such as the need for materials to move in and out of cell. this usually involvves the surface-area-to-volume ratio 2) cell division apparatus. If cells are too large/toosmall the mitotic spindle will not function properfly.

Answer 7

cell size is set as it goes through its differentiation process to become a particular cell type. All the adaptations come together to produce the most efficient cell possible for the specific function it has

Answer 8

the surface-area-to-voume ratio limits the size a cell can reach. Most of the chemical reactions of life occur inside a cell, and the size of the cell affects the rate of those reactions. Volume: * In a cell, the **rate of heat and waste production**, and **rate of resource consumption**, are dependent on the volume. Surface area: * The surface of the cell, the membrane, **controls what materials move in and out of the cell**. Hence, A cell with **more surface area per unit volume** can move **more** materials in and out of the cell, for each unit volume of the cell. This means that a **large cell**, compared to a small cell, has **less surface area** to bring in materials that are needed and to get rid of waste. Because of this, cells are limited in the size they can reach and still be able to carry out the functions of life. This means that **large animals** do **not** have larger cells; instead, they have **more cells**.

Answer 9

As the width of an object such as a cell increases, the surface area also increases, but at a much slower rate than the volume: * The volume increases by a factor calculated by cubing the radius * At the same time, the surface area increases by a factor calculated by squaring the radius.

Answer 10

1) changes in shpae 2) cellular projections, both inward and outward 3) Location relative to sources of nutrients and means of transporting away wastes 4) How the cells fit together at a specific location chatgpt also includes: * Being small to maximize diffusion efficiency. * Developing thin, elongated, or flattened shapes (e.g., red blood cells, nerve cells). * Having microvilli to increase surface area (e.g., intestinal epithelial cells). * Possessing internal compartmentalization (e.g., organelles in eukaryotic cells) to optimize metabolic processes.

Answer 11

A type of blood cell that is made in the bone marrow and found in the blood. Erythrocytes contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. (**Red blood cell**)

Answer 12

the biconcave disc shape of red blood cells allow a greater surface-area-to-voume ratio. Their size coupled with their flexibility als allows them to squeeze through small capillaries to deliver oxygen to all cells of the body.

Answer 13

a part of the human kidney. the cells lining this tubule have several unique adaptations that increase their ability to reasorb fluids and secrete ion: 1) cube shaped cells closely packed together to use space efficiently 2) cells have tiny projections called microvilli pointing outwards into the lumen of the tubule in whcih fluid flows. this brush border increases the surface area 3) large numbers of mitochondria, allowing active transport of ions and other substances 4) invaginations (channels) are on the opposite side of the cell (thus on the opposite side from of the lumen as well) increases the surface area of the cell to help transport

Answer 14

the functional unit of the lungs. * the alveoli increase surface area of the lung to maximise gas exchange * they must also be able to function as the lungs and expand and contract during breathing process * they're at the very end of the respiratory tract and can be thought of as empyt sacs lined by a wall that's one cell thick

Answer 15

1) **Deoxygenated blood arrives:** Blood with low oxygen (O₂) concentration and high carbon dioxide (CO₂) concentration flows into the lungs via the pulmonary artery. 2) **Oxygen diffusion:** The alveoli have a high concentration of O₂ from inhaled air, while the blood in the capillaries has a low O₂ concentration. Oxygen diffuses across the thin alveolar membrane into the blood, binding to hemoglobin in red blood cells. 3) **Carbon dioxide removal:** The blood has a high CO₂ concentration, while the alveolar air has a low CO₂ concentration. CO₂ diffuses from the blood plasma into the alveolus to be exhaled. 4) **Oxygenated blood transport:** The now oxygen-rich blood leaves the lungs through the pulmonary vein, delivering oxygen to body tissues. 5) **Maintaining diffusion gradients**: Continuous blood flow and ventilation sustain the oxygen and carbon dioxide concentration gradients, ensuring efficient gas exchange.

Answer 16

1) Type I pneumocytes 2) Type II pneumocytes 3) Alveolar macrophages

Answer 17

Type I pneumocytes cover 95% of the alveolar surface. Their major function is to allow gas exchange between the alveoli and the capillaries. They have several interesting adaptations: * they are thin and flat in shape to increase the surface area and minimize diffusion distance * a shared basement membrane with the endothelium (lining) of lung capillaries, which minimizes diffusion distances for respiratory gases * they are tightly joined to each other so that fluids cannot enter the alveoli from the capillaries.

Answer 18

Type Il pneumocytes make up less than 5% of the surface, found between the type I pneumocytes. Their role is to produce pulmonary surfactant, which reduces surface tension and prevents the alveoli from collapsing and sticking to each other during the breathing process. Adaptations include: * a cube shape, providing a larger cytoplasmic area for the organelles producing the surfactant * microvilli oriented towards the alveolar sac, increasing the surface area and allowing more surfactant secretion * a cytoplasm that contains many organelles involved with surfactant production and its secretion, including secretory vesicles (called lamellar bodies) * the ability to transform into type I pneumocytes when needed.

Answer 19

The alveoli contain macrophages, which are white blood cells. You do not need to know about these for the IB, but they perform endocytosis to remove harmful substances and organisms from the inhaled air.

Answer 20

Cardiac muscle fibres occur in the heart, and they have banded cells like the striated skeletal muscle cell. However, they also have further adaptations to perform their unique functions. They: * are composed of branching, striated cells * have a single nucleus per fibre/cell * are connected at the ends by intercalated discs. Cardiac muscle fibres are shorter in length than striated skeletal muscle fibres. Because of their branching cells, and the connections between them, cardiac muscle fibres coordinate a contractile process involving the whole heart in order to pump blood successfully throughout the body.

Answer 21

It has been debated whether striated skeletal muscle fibres should be considered cells: * These cells are larger than most animal cells. * Once they are formed, skeletal muscle fibres do not follow the usual pattern of cell division. They do not expand by producing more cells in adult organisms, but grow when their supporting satellite cells fuse with the existing fibres. * Also, when muscle fibre cells are severely damaged, they do not go through the usual process of cell death (apoptosis) followed by cell replacement. However, even with all these unique characteristics, striated muscle fibres still have many of the organelles and features discussed when describing cells.

Answer 22

* One of the smallest human cells 3 um in width, 50 um in length * Flagellum (mid-piece) present that allows motility. Mitochondria located near the flagellum to supply energy for movement * Shape includes a head and a tail region and is streamlined for speed and efficiency * Very few cytoplasmic organelles such as endoplasmic reticulum, Golgi apparatus or ribosomes * Continually produced in vast numbers throughout the life of a male * Head has a specialized secretory vesicle called the acrosomal vesicle that helps the sperm penetrate the egg's outer coat * Contains a haploid nucleus

Answer 23

* One of the largest human cells 120 um * No flagellum present, the cell is non-motile * Shape is non-streamlined. It is spherical * Most cytoplasmic organelles are present plus specialized storage structures for initial embryo development * All the early gamete-forming cells are present before birth. No new egg-forming cells are produced after birth * Has special secretory vesicles just under the plasma membrane that release their contents after one sperm penetrates the egg to prevent other sperm from entering * Contains a haploid nucleus