CELL BIOLOGY Flashcards

Question

Active transport

Answer 1

``` When substances are transported across the membrane using energy, often against a concentration gradient. ◦ From low to high conc ◦ Always uses carrier proteins ◦ Crucial in allowing a cell to maintain an internal environment that differs from its external environment ```

Answer 2

``` Uses energy to allow movement of large, polar molecules across the membrane ◦Exocytosis ◦Endocytosis ◦ Pinocytosis (drinking) ◦ Entry of extracellular fluid and substances ◦ Phagocytosis (eating) ◦ Entry of large particles like cell debris or bacteria ```

Answer 3

Protein channels that facilitate the diffusion of water through membranes

Answer 4

If water can still pass through the membrane, then it will move to achieve equilibrium!

Answer 5

Osmosis is the net diffusion of water molecules across a semi-permeable membrane Just like regular diffusion, but of water! The concentration gradient is called an osmotic gradient The pressure that causes the water to move along this gradient is called osmotic pressure.

Answer 6

Hypotonic: The solution with the lower conc of solute (and high conc of water) Hypertonic: The solution with the high conc of solute (and lower conc of water) Isotonic: Both solutions have the same conc of solutes

Answer 7

the chemical reactions in the body's cells that change food into energy

Answer 8

Blood- the medium of transport Heart- the pump Vessels- the pathway

Answer 9

it is a complex mixture containing: 1. cells- RBS WBC Platelets 2. Plasma RBCs are flattened discs which carry oxygen around the body. Oxygen (O2) is held loosely by a protein called haemoglobin. Haemoglobin has an iron molecule at its core, which gives it a red colour. WBCs are much fewer in number. They help protect the body against disease Platelets are tiny cells which enable the blood to clot. Plasma is a yellow liquid in which the cells float.

Answer 10

The energy to move blood through the body is provided by the heart. 70 mL per beat 280 L per day The heart begins beating in the embryo 3 wks after fertilisation - from a tiny cluster of cardiac cells

Answer 11

``` The pathway which carries the blood is a system of tubes called blood vessels There are three major kinds of vessels: 1. Arteries 2. Veins 3. Capillaries ```

Answer 12

``` Arteries always carry blood AWAY from the heart. Arteries: have a red-coloured lining have thick, muscular walls usually carry blood under high pressure ```

Answer 13

``` Veins always carry blood TO the heart. Veins: have a bluish lining have thin walls usually carry blood under low pressure ```

Answer 14

Arteries branch into smaller and smaller arterioles. Eventually they become capillaries, tiny vessels which reach into every tissue. Capillaries branch into larger and larger venules, which then join to become veins.

Answer 15

``` The lymphatic system performs two roles: 1. Circulation 2. Disease resistance (immune response) Since the heart is constantly pumping, fluid is always being pushed into body tissues. Without the lymphatic system, those tissues would swell up. The lymphatic system has: 1. Lymph basically plasma (no cells) 2. Lymph vessels thin walled with valves 3. Lymph ducts larger vessels which empty lymph into veins 4. Lymph nodes bean-shaped lumps for lymph collection the location of WBC development ```

Answer 16

Plasma leaves the blood stream, entering between tissue cells. This intercellular fluid moves through the tissue, collecting wastes as it goes. The fluid passes into lymph capillaries and is now called lymph. Lymph moves along the vessels until it reaches a lymph node where WBCs destroy pathogens. Lymph then moves through to a lymph duct, which returns the fluid to a large vein, completing the circuit.

Answer 17

In the human body there are two kinds of respiration: 1. Cellular respiration 2. Pulmonary respiration Cellular respiration is a chemical process during which energy molecules are broken down. Pulmonary respiration is the process by which gases are breathed in and out.

Answer 18

The respiratory system has two major sections: 1. Upper respiratory system 2. Lower respiratory system

Answer 19

The nose and mouth are air entry points. The pharynx connects the mouth with the trachea. The epiglottis is a flap of tissue which prevents food going down the airway The trachea is a rigid tube lined with cartilage The lungs are spongy tissue made of tubes and sacs. Alveoli (singular alveolus) are tiny sacs grouped in clusters at the end of the bronchioles. They have very thin membranes and a high sa:vol. They are supplied by a dense network of capillaries. It is here that gas exchange occurs between air and the blood stream. The diaphragm is a sheet of muscle separating the chest from the abdomen. The inter-costal muscles join the ribs to each other

Answer 20

Inter-costal muscles pull the ribs apart The diaphragm contracts These two actions expand the chest cavity, creating a lower pressure. The lung tissues expand to fill the chest cavity Air rushes in through the mouth & trachea (etc.) During its passage down the airways, air is filtered by cilia, warmed and humidified Once it reaches the alveoli, oxygen passes through the membrane into the blood in the capillaries 8. At the same time, CO2 diffuses from the blood out into the alveoli 9. The inter-costal & diaphragm muscles relax 10. The chest cavity shrinks 11. Air is expelled

Answer 21

Respiratory disease can be caused by: 1. Pathogens (e.g., bacteria) 2. Lifestyle impacts (e.g., smoking)

Answer 22

``` Solar energy is converted to chemical bond energy in the process of photosynthesis. This bond energy is then released for cellular use via the process of respiration. Photosynthesis occurs in chloroplasts. occurs in two phases: Phase 1: Light reactions - require sunlight energy ```

Answer 23

Organisms which construct their own energy storage molecules (‘food’) are called autotrophs. Organisms which gather their energy from other organisms are called heterotrophs

Answer 24

``` The two major energy storage molecules in biological systems are glucose and ATP Glucose - quite small - quite stable - universal in the biosphere - not useable at the organelle level ATP: - adenosine tri-phosphate - ADP + P = ATP - the creation of the bond stores energy - breaking the bond liberates energy - ATP directly fuels organelle activity ```

Answer 25

CO2 + H20 ------ C6H12O6 + O2

Answer 26

Light: AKA “Light Dependent Reactions” as they require solar energy Occur in the thylakoids of grana Does not result in the production of sugar Dark- AKA ‘Light Independent Reactions’ as they occur constantly Depend on the outputs of the light reactions Occur in the stroma of the chloroplasts Results in the formation of sugars (CH2O)n Process  Calvin Cycle

Answer 27

The complete set of rainbow colours is known as the visible light spectrum. The visible spectrum is itself only a small fraction of the complete electro-magnetic (EM) spectrum. All EM energy, including light, moves in waves. The distance from the peak of one wave to the peak of the next is known as its wavelength

Answer 28

Red light is absorbed most by chlorophyll, followed by blue light. they energise electrons and increase rate of photosynthesis Green and yellow light are mostly reflected. This is the reason plants look green

CELL BIOLOGY Flashcards

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