Yr 10 mocks - Biology

Cell membrane

protects cells and transports things in and out of the cell

Nucleus

controls the activities of the cell and contains chromosomes

Mitochondria

Where most energy is released through respiration

Ribosomes

Tiny structures where protein synthesis occurs

Cell wall

maintains cells shape and is made of celluose

Chloroplasts

Trap light energy used for making sugars by photosynthesis

Vacuole

Large cavity filled with cell sap

Cytoslpasm

where most chemical reactions take place

What is a prokaryotic cell?

a simple cell that lacks a nucleus and other organelles

What is a eukaryotic cells

complex cells that contains a nucleus and other organelles

Differences between eukaryotic and prokaryotic cells

prokaryotic contains dna outside the nucleus but eukaryotic contains dna inside the nucleus

eukaryotic cells are bigger than prokaryotic cells

How to use a microscope in 6 steps

1. take a glass slide and place your specimen on it

2. Add a drop of water or stain to your specimen

3. Place the cover slip on your slide

4. Place your slide on the stage in the lowest magnification object lens

5. Look through the eye piece lens and focus on the specimen using the coarse focussing wheel

6. change the objective lens for a higher magnification and refocus

Why are electron microscopes used in biology?

Have a higher resolution and magnification than light microscopes but are more expensive

Specialised cells

cells that have been differentiated to carry out specific functions

for example

red blood cells -biconcave disk increases surface area so more oxygen can be carried

root hair cells - large surface area increases rate or absorption or water and minerals

What are tissues, organs and organ systems made from?

Tissues - a group of specialised cells

Organs - tissues that work together to do a particular function

Organ systems - organs that perform particular functions

Precautions to take when growing microbes

Boil agar - kills bacteria

Flame inoculating loop - sterilises it

Tape down the lids of the petri dish - stops bacteria in air from contaminating the plate

Incubate at 25 degrees - stops human pathogens from frowning

Store upside down - stops condensation dripping and disturbing microbe growth

Chromosomes key facts

Found in the nucleus of eukaryotes

Made out of DNA that can be separated into genes that determine our characteristics

How does a cell divide by mitosis?

The cell replicates their DNA and makes 2 copies every chromosome and every sub cellular organelle

One set of chromosomes push to the other end of the cell as the other until the nucleus divides

the cytoplasm and cell membrane divide to form 2 new identical cells

Stem cells deffinition

undifferentiated cells that continue dividing and can be used to treat lukemia and grow organs for transplants

adult stem cell vs embryonic stem cell

embryonic : can develops into almost any cell in the body but the embryo is killed

Adult : no killed embryo but cannot adapt into as many cells and it takes longer

How can stem cells be used to clone plants?

1. cut meristem tissue sample off plant

2. plant it in an agar plate to grow into tiny platelets

3. plant platelets into compost and the clones will grow and be genetically identical to the original plant

Define diffusion

the spreading out of particles in a gas or any substance in a solution

What factors affect the rate of diffusion?

concentration gradient (the larger difference in concentration, the faster the rate of diffusion)

temperature (higher temps = faster rate)

surface area (bigger surface area = faster rate of diffusion)

examples of discussion in plants or animals

gas exchange in lungs or co2 diffusing into leaves

Osmosis

the diffusion of water across a partially permeable membrane, this makes the cells/tissue bigger and rigid

what affect does osmosis have on cells

water moves into cells

the vacuole swells

the cytoplasm is pressed against the cell wall

the cell becomes rigid

plant becomes rigid

active transport

active transport is a process when substances move across a partially permeable membrane against the concentration gradient

differences between diffusion and active transport

active transport = requires energy and travels against concentration gradient

diffusion = no energy needed energy and travels with concentration gradient

Examples of active transport

sugars into blood

minerals from so into root hair cells

What are enzymes and what are they made out of?

biological catalysts

made from proteins

describe the lock and key theory

1. substrate fits perfectly in to the active site of the enzyme

2. substrate splits once the enzyme catalyses the reaction and both parts leave the activation site

3. enzyme is ready to use again

enzyme reactions can be affected by …

temperature- too hot or too cold causes them to denature

ph - to high or to low they denature meaning the substrate no longer fits into the active site

what happens when an enzyme denatures?

the reaction stops

Amylase

found in salivary glands, pancreas and small intestine and turns starch into sugar

Protease

found in stomach, pancreas and small intestine and turns proteins into amino acids

lipase

found in small intestine and pancreas and turns lipids (fats) into fatty acid and glycerol

use of hcl in stomach

breaks down food and kills bacteria

use of bile in digestion

produced in liver and stored in gall bladder

neutralises the stomach acid as not to damage small intestine

emulsifies fats for enzyme digestion

Blood pathway in the heart

what are the 4 main blood vessels attached to heart

pulmonary artery

pulmonary vein

vena cava

aorta

differences between 3 main types of blood vessels

artery - carries blood away from heart at high pressure. small lumen and thick elastic walls

vein - carries blood towards the heart at low pressure, valve to stop back flow of blood, large lumen and thinner walls

capillaries- carry blood through the organs and exchanges o2 and co2 with cells

what are the roles of the 4 major components of blood

red blood cells - carry o2 to all organs

white blood cells - form part of the bodies defence system against microorganisms

platelets - help blood to clot

plasma - carries nutrients, hormones and proteins to the parts of the body that need it

What is the cause of coronary heart disease?

build up or fatty deposits in the coronary artery usually affected by smoking, a fatty diet, obesity, lack of physical activity and genetics

what and where is the hearts natural pace maker?

the upper part of the right atrium and continuously generates electrical impulses setting a normal rhythm and rate.

stents

mesh tubes inserted into coronary artery to widen artery by pushing fats to the side. involve a minimally invasive operation

statins

pills that thin blood and lower cholesterol with involve no operation but you have to take the pills for life

Health definition

state of physical and mental wellbeing and can be affected by both communicable and non communicable factors

examples of communicable causes of disease

pathogens, viruses, bacteria, coughing and sneezing

examples of non communicable causes of disease

lifestyle, smoking, diet, exercise, stress, genetics

why are malignant tumours cancerous

cells can break off and spread to different parts of the body though the blood stream and form secondary tumours

state 2 factors that can cause cancer

smoking and diet/weight/physical activity

pathogens

microbes that cause disease, including bacteria, viruses, protists and fungi

how do pathogens spread

they can be airborne, through food animals or through contact

How do pathogens cause disease

They invade host cells and reproduce/replicate themselves causing the cells to burst and spread to infect other organisms

symptoms of measles

(a viral disease) causes a fever, red rash and if not treated blindness, brain damage and fatal complications

symptoms of HIV

(a viral disease) flu symptoms and can lead to AIDS which kills the immune system

Symptoms of Tobacco Mosaic Virus

(a viral disease) mosaic pattern in leaf and the plant does not photosynthesise

Rose black spot symptoms

(a fungal disease) the leaves fall early and weaken plant by reducing area for photosynthesis

Malaria symptoms

(a protist disease) episodes of fevers and shaking. can be fatal

symptoms of salmonella

(a bacterial disease) cramps, fever, vomiting and diarrhoea

Symptoms of Gonorrhoea

causes yellow discharge from penis/vagina and pain when urinating

Phagocytosis

A phagocytes (type of white blood cell) moves towards pathogen

The phagocyte engulfs the pathogen

The phagocyte digests the pathogen and the pathogen diffuses inside the phagocyte.

The phagocyte then moves towards another pathogen and the process repeats

Lymphocytes

Type of white blood cells that produce specific antibodies to bind to the antigens in the pathogens surface. this causes microorganisms organisms to clump together so they are easier to digest by phagocytosis

The bodies non-specific defence

Skin - barrier, blood clots form in open wounds

Stomach - HCL destroys pathogens in food

Eyes - release enzymes in tears

Nose/throat - mucus traps and removed pathogen via coughing/sneezing

What are vaccines?

an injection containing a weakened or dead pathogen. this makes our bodies produce antibodies to destroy the pathogens in the vaccine. memory cells in our body remember how we did that so if we ever get the real pathogen we can produce antibodies much faster and in much bigger numbers meaning the pathogens are killed before you even feel ill

Why do antibiotics only work on bacteria not viruses

viruses are not alive and not made of cells and are hard to get to as they live inside our cells

why shouldn’t antibiotics be used to treat everything?

over time through mutation and selection, bacteria can develop defense mechanisms against the antibiotics

describe the process involved in testing a new drug

1. drug is tested on computer models and human cells grown in lab

2. drug tested on animals

3. drug tested on healthy humans (clinical trial)

4. tested on volunteers with the illness

5. tested on larger number of volunteers to monitor side affects, dosage and effectiveness

6. drug is approved and can be prescribed

Homeostasis definition

The maintenance of a constant internal environment and maintaining optimum conditions for enzyme action

Nervous system deffinition

the system that allows our bodies to respond to changes in the environment

How does the nervous system work

1. a the stimulus is detected by receptor cells in our sense organs

2. The coordinator (the CNS) coordinates the bodies response to the stimulus

3. The effector brings about the response (eg muscles contract or glands secrete)

4. Response

What is the cns and what is it made from

the central nervous system which consists of the brain and spinal cord and 3 neurones: sensory, relay and motor

What do sensory neurons do?

send electrical impulses from receptor cells to relay neurons

What do relay neurons do?

Send electrical impulses from sensory neurons through the CNS to motor neurons

What do motor neurons do?

send electrical impulses from the CNS to an effector (muscle or gland)

What happens at a synapse?

Chemicals called neurotransmitters diffuse across the gap and continues along the gap to another neurone

What are reflex actions

rapid involuntary movements which help with survival of an organism/prevent further damage to a particular area.

In a reflex action, the pimple does not need to do as far as the brain and instead goes to the spinal cord

Reflex arc

1. the stimulus

2. the receptor cells

3. sensory neurons

4. synapse

5. relay neurons

6. (CNS)

7. synapse

8. motor neuron

9. effector

10. response

Reaction time practical

1. collection a 1m ruler and a blind fold

2. the subject sits at the table with dominant hand over the edge

3. the partner holds the ruler vertically above their fingers

4. without warning they drop the ruler and measure where there subject caught it

5. repeat 4 more times

6. (for auditory reaction time) repeat 1-6 bit say release and blind fold subject)

7. (for tactile reaction time) repeat 1-6 but tap non dominant hand before letting go