Biology - Year 9

What does MRS GREN stand for?

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition

What is the purpose of MRS GREN

Characteristics of life

What are the 5 kingdoms of living things

Animals, Fungi, Protoctists, Plants, Bacteria

Plant cells differ from animal cells in what ways?

They have cellulose cell walls, chloroplasts (for photosynthesis), and vacuoles. They use starch for energy as opposed to animal cells using fats and glycogen for energy.

What are the cell walls of fungi cells made of?

chitin

All types of living thing have nuclei except for...

Bacteria, they have a chromosome

Prokaryotic

All organisms which do not have a nucleus and other organelles (primarily bacteria)

Eukaryotic

All organisms which have cells that have a nucleus bound in a membrane (can be unicellular)

Three ways in which bacterial cells differ from a eukaryotic cell is:

Has no nucleus, has a flagellum, has no mitochondria

A pathogen is...

A microorganism that causes disease

Cells are full of...

Organelles (like mitochondria, ribosomes, nucleus, etc.)

Cells come together to form...

Tissues

Tissues come together to form...

Organs

Organs come together to form...

Organ Systems

Purpose of the nucleus

store genetic information

Purpose of ribosomes

Create proteins: "Protein synthesis"

Purpose of cytoplasm

Supports cell can is where chemical reactions take place

Chloroplasts contain what to do what task

they contain chlorophyll to perform photosynthesis

Difference between cell wall and cell membrane

Cell wall is rigid and provides protection against the external environment, while the cell membrane is thin, delicate, and flexible, to maintain the internal environment of the cell. Cell membrane also allows diffusion of substances in and out of the cell.

Differences between an animal cell and plant cell

Animal cell has no cell wall, chloroplasts, or vacuole. Animal cells store energy in fats and glycogen, plant cells with starches. Plant cells photosynthesise.

Similarities between animal cell and plant cell

They both have nuclei, cell membranes, ribosomes, mitochondria, cytoplasm,

If a cell is flaccid, then it is...

in an isotonic solution, so the water potential both inside and outside the cell are the same and the cell is normal shape

If a cell is turgid, then it is...

in a hypotonic solution, so the water potential inside the cell is greater than outside and water moves into the cell. Cell membrane and vacuole expand with the incoming water and presses against cell wall

If a cell is plasmolysed, then it is...

in a hypertonic solution, so the water potential outside the cell is greater than inside and water moves out of the cell. Cell membrane and vacuole shrink.

A salt in water solution is...

Hypertonic

Distilled water is...

isotonic

Osmosis

The movement of molecules (usually water) through a semi-permeable membrane from an area of high water potential to low water potential

Diffusion

The movement of molecules from a high concentration area to a low concentration area

Active Transport

Requires ATP energy, moves molecules against the concentration gradient (from low concentration to high)

Factors increasing rate of diffusion

Steeper concentration gradient, higher temperature, shorter distance to be diffused, higher surface area to volume ratio

Word equation for aerobic respiration

Glucose + Oxygen --> Carbon Dioxide + Water (+ energy)

Balanced symbol equation for aerobic respiration

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O

Word equation for anaerobic respiration in animals

Glucose --> Carbon Dioxide + Lactic Acid

Word equation for anaerobic respiration in plants

Glucose --> Carbon Dioxide + Ethanol

Role of diffusion in gas exchange

Allows a gas (either from the air or from the lungs) which is in high concentration to enter an organism - where it would be in lower concentration - for respiration

What gas does a plant take in when respiring through photosynthesis?

Carbon Dioxide (Equation: H2O + CO2 ---Chlorophyll---> O2 + C6H12O6, where O2 is waste and C6H12O6 is the product)

Why do plants photosynthesize?

To produce glucose, which can be broken down to create energy

Gas exchange in photosynthesis involves the taking in of __________ in exchange for _________

CO2, O2

How is the structure of a leaf adapted for gas exchange?

Thin, so less distance for gasses to diffuse; higher surface area, so that there is more of the leaf in contact with the gas relative to its serface area; has stomata (holes), allowing gasses to get in and out easily

Purpose of stomata

Little "mouths", they can open and close (or position themselves somewhere in between) in order to regulate gas exchange by allowing gasses in or out, or to prevent water loss in hot environments by closing.

How plants respire in the day and night

There is no light in the night to perform photosynthesis, meaning no glucose for respiration will be produced. Since the cells of a plant will only need a relatively small amount of glucose to respire compared to the amount that is produced in the day, the plant takes the excess glucose and stores it, so that the plant can breathe during the night. Oxygen can always be taken in, and so is not a problem in the night.

During the night, what gasses will be going in and out of a leaf (net)?

Oxygen in and carbon dioxide out, as in the night no photosynthesis can take place and so there is no need to draw in CO2, only respiration is taking place so O2 is being taken in for respiration and CO2 leaving as a waste product

At noon, what gassess will be going in and out of a leaf (net)?

Carbon dioxide in and oxygen out, as at noon more photosynthesis is taking place than respiration in broad sunlight, and so more carbon dioxide is needed for the photosynthesis reaction than the respiration reaction. Oxygen is a waste product of photosynthesis and will be leaving the leaf.

Thorax

lungs

Purpose of intercostal musces

They are in between the ribs, and help move the ribs in or out with a breath

Purpose of pleural membrane

Provides a low friction surface for the lungs to slide against when breathing

Purpose of diaphragm

Muscle which controls size of the lungs, if it makes the lungs bigger, air gets drawn in due to drop in pressure, if it makes the lungs smaller, air gets pushed out due to spike in pressure

When the diaphragm is contracted, you are...

exhaling

Conseqences of smoking

Lung and/or heart disease, cancer

Why does smoking cause heart disease?

Plaque forms in blood vessels, reducing blood flow (therfore making it difficult for oxygen to get around) or potentially clotting a vessel entirely, causing a stroke if in the brain or a heart attack

Nuclei in pollen grain

Tube, generative

Why is one side of the heart thicker than the oher

It needs more muscle to pump blood further

Why does heart rate increase when exercising

Muscles moving --> require more energy --> need to respire more --> needs more oxygen for respiration --> needs more blood to carry the oxygen --> heart pumps faster to deliver increased amounts of oxygen

Process of immunisation by vaccination

You are injected with weakened or dead pathogens, and your body treats it as a real infection even though it can do no damage. Lymphocytes produce antibodies to fight the infection, and when the correct antibodies are found the memory cells remember them for when you actually encounter the pathogen, making the immune reaction faster.

How are arteries adapted for function

They are thicker, as they need more muscle/strength to withstand greater pressure from the heart pumping hard to travel around the body.

How are veins adapted for function

They have valves, because the pressure in the veins (further from the heart) is less and blood is more likely to flow backwards, and valves prevent this

How are capillaries adapted for function

They are thin, allowing for easy diffusion over a short distance

Plants can reproduce asexually by...

Using runners or cuttings, self pollination

Process of plant fertilisation through pollen

Pollen grain lands on stigma of plant, tube nucleus grows a pollen tube down the style while the generative nucleus splits into two sperm cells. When the tube contacts the ovary, it opens up, allowing the sperm cells to exit and fertilise an ovule. The fertilised egg will turn into a seed and the ovary into a fruit.

Process of seed germination

Seed has an energy store (endosperm) to allow it to last until it can photosynthesise. When the seed is planted, it absorbs water which activate enzymes (amylase) to convert the endosperm to energy. The plant uses this energy, as well as additional water takein through osmosis, to grow a root which breaks out of the seed coat.

Reproductive organ of a plant, carries out sexual reproduction

Flower

Seed leaf of a seed (leaf inside a seed)

Cotyledon

Male gamete of a flower is contained in the

pollen (a gamete is a sex cell, so in this case a sperm cell which is stored in the pollen)

Differences of sexual and asexual reproduction

Asexual reproduction produces genetically identical offspring, doesn't require two parents, offspring has less response to change and is therefore more vulnerable to change, doesn't require gametes. Sexual reproduction is the opposite