Year 8 Biology Flashcards

7 characteristics for all living organisms (MRS NERG):

Movement

Respiration

Sensitivity

Nutrition

Excretion

Reproduction

Growth

Unicellular organisms

One cell organisms capable of all 7 life processes, e.g. amoeba

Cell membrane

Selectively permeable- controls what enters and leaves the cell

Cytoplasm

Where chemical reactions take place, main part of cell, jelly-like substance

Nucleus

Control centre of cell where genetic information is stored in the form of chromosomes (DNA)

Mitochondria

The site of aerobic cellular respiration

Nuclear membrane

Membrane that surrounds the nucleus

Respiration

Respiration is the process by which an organism makes energy

Cell wall

Provides support, made of cellulose

Vacuole

Contains cell sap, makes cell rigid and provides support

Chloroplasts

Contains chlorophyll, traps light, is used for photosynthesis

Ratio of mitochondria to chloroplasts in plant cells

Plant cells have more chloroplasts than mitochondria

The place where chloroplasts are found in plants

Chloroplasts are only found in the green parts of plants

Parts of a bacterial cell and extra information:

Plasmids- Small circular loops of DNA

Non-cellulose cell wall

Their DNA is in the form of a loop

They are not joined together with other cells and tissues

Some bacteria have a flagellum, this is a tail-like structure that helps them move/swim

The reagents used in microscopes for plant and animal cells

Iodine- Plant cells Methylene blue: Animal cells

Specialised cells

Root hair cells

Palisade cells

Guard cells

Red blood cells

White blood cells

Nerve cells

Sperm cells

Egg cells

Ciliated cells

Diffusion

Diffusion: The random movement of particles from a place of high concentration to a place of low concentration

Net Movement

The number of particles moving in one direction, minus the number moving in the other

Levels of organisation

Levels of organisation: cell, tissue, organ, organ system, organism

Circulatory system

made up of Heart, blood, blood vessels and lymphatics. This is the body’s delivery system. I circulates blood to deliver oxygen and nutrients to each part of the body.

Digestive system

made up of mouth, stomach, large and small intestines, liver and gallbladder. Breaks down food to be used for energy

Endocrine system

made up of pituitary and thyroid glands, ovaries, testes, pancreas and renal glands. It regulates, coordinates and controls a number of body functions by secreting chemicals into the bloodstream. These secretions help control moods, growth, development and metabolism.

Muscular system

made up of muscle fibres, tissue and tendons. Helps move the body and move materials through the body.

Nervous system

made up of brain, spinal chord and nerves. Uses the information received from the brain to coordinate all of your actions and reactions by carrying messages (impulses) around the body.

Reproductive system

made up of mammary glands, penis, uterus, epididymis, ovaries and testes. Ensures that humans are able to reproduce and survive as a species

Respiratory system

made up of nose, larynx, trachea, diaphragm, bronchi and lungs. To supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing.

Skeletal system

made up of bones, cartilage and joints. Provides the shape and form for our bodies in addition to supporting and protecting our bodies, allowing bodily movement, producing blood cells and storing minerals.

Excretory system

made up of kidneys, ureters, urinary bladder and urethra. To filter out excess fluid and other substances out of the bloodstream. Some fluid gets reabsorbed by your body but most gets expelled as urine..

Integumentary system

made up of hair, skin and nails. Helps with body temperature regulation, cell fluid maintenance, synthesis of vitamin D and detection of stimuli

Immune system

made up of thymus, lymph noes, spleen and lymphatic vessels. To keep germs and other foreign substances out of the body and destroy any that get in

2 main functions of the circulatory system

Transportation of substances, Protection against disease

3 main components of the circulatory system

3 main components: Heart (pump), Blood, Blood vessels

4 components of blood

Red blood cell, white blood cell, platelets and plasma

Red blood cell

Red blood cell: carries oxygen. Contain haemoglobin (rich in iron). Biconcave shape to provide a large surface area for the diffusion of oxygen. No nucleus to provide more space for haemoglobin.

White blood cell

White blood cell: Defends the body against disease. Large cells that contain a nucleus. There are 2 types: lymphocytes- make antibodies and phagocytes- engulf and digest microorganisms

Platelets

Platelets: Convert fibrogen to fibrin. Fibrin forms a mesh that traps blood, Important in blood clotting and scab formation.

Plasma

Plasma: Transports blood cells, digested food molecules, carbon dioxide, urea and hormones. Yellow coloured liquid

Ratio of white blood cells to red blood cells and their size and whether they contain a nucleus

There are more red blood cells than white blood cells

White blood cells are bigger than red blood cells

A red blood cell doesn’t have a nucleus, a white blood cell does

Arteries

Arteries- Carry oxygenated blood away from the heart. Thick walls with muscle and elastic fibres to withstand high pressure, muscle and elastic fibres within the walls also allow the artery to expand and recoil with each surge of blood

Veins

Veins- Carry deoxygenated blood into the heart. The lumen is large and reduces friction as the blood moves through. Blood is moving at a low pressure, so the walls are thin. Very few muscle and elastic fibres because blood does not surge through veins. Valves are present to prevent the backflow of blood.

Capillaries

Capillaries- Allow the diffusion of substances between the blood and the body’s cells or vice versa. Walls are 1 cell thick, providing a large, thin surface for diffusion.

The heart

The heart is a unidirectional pump- it pumps blood in one direction. Valves are present to prevent the backflow of blood. The right side pumps deoxygenated blood back to the lungs, the left side pumps oxygenated blood to the organs of the body

Journey of the blood through the heart:

1. Deoxygenated blood enters the right atrium through the vena cava

2. Blood moves into the right ventricle

3. Blood is pumped into the pulmonary artery

4. The pulmonary artery carries deoxygenated blood to the lungs

5. The blood becomes oxygenated in the lungs

6. Oxygenated blood leaves via the pulmonary vein

7. Blood enters the left atrium

8. Blood moves into the left ventricle

9. Blood is pumped into the aorta, which carries oxygenated blood around the body to all the body cells where it is used in respiration

What are renal and hepatic associated with?

Renal- associated with kidneys, Hepatic- associated with livers

Vena Cava function

Vena cava- Carries deoxygenated blood from the body back into the heart

Pulmonary artery function

Pulmonary artery -Carries deoxygenated blood from the heart to the lungs

Pulmonary vein function

Pulmonary vein- Carries oxygenated blood from the lungs to the heart

Aorta function

Aorta- Carries oxygenated blood from the heart around the body

Hepatic artery function

Hepatic artery- Carries oxygenated blood to the liver

Hepatic vein function

Hepatic vein- Carries deoxygenated blood back to the heart. Carries digested food (glucose and amino acids) from the liver around the body

Hepatic portal vein function

Hepatic portal vein- Carries digested food from the small intestine to the liver

Renal artery function

Renal artery- Carries oxygenated blood (rich in urea) to the kidneys for excretion

Renal vein function

Renal vein- Carries deoxygenated blood (low in urea as it has been purified in the kidney) back to the heart

The main role of the kidneys

Regulates the water content in the blood to make sure we have just the right amount of water in the blood. They excrete/remove the toxic waste products of metabolism

How the kidney works

1. Blood enters via the renal artery

2. Liquid and many dissolved substances are filtered out in the cortex

3. In the medulla, water and some of the substances are reabsorbed back into the blood in a controlled way until normal concentrations are reached

4. Any water and dissolved substances left over pass into the urine, which collects in the renal pelvis

5. Urine passes into the ureter

6. Urine is stored in the bladder

7. Urine is passed out via the urethra