Structures and Functions in Living Organisms Flashcards
What do most organisms have in common?
8 life processes
What are the eight life processes?
nutrition excretion movement growth respiration response to stimuli reproduction controlling their internal enviroment
What is nutrition?
needing nutrients to provide energy and raw materials for growth and repair
Name 2 waste products (excretion)
carbon dioxide and urine
What are all living organisms made up of?
cells
What are the tiny structures inside a cell called?
organelles
Name the organelles found in a typical animal cell
cell membrane
cytoplasm
nucleus
mitochondria
Name the organelles found in a typical plant cell
cell membrane cytoplasm nucleus mitochondria cellulose cell wall permanent vacuole chloroplasts
Similar cells are organised into….
tissues
Tissues are organised into…
organs
Organs make up…
organ systems
How do cells release energy from food?
by respiring
aerobically and anaerobically
How can substances move in and out of cells?
diffusion
osmosis
active transport
What are the levels of organisation in an organism?
organelle cells tissues organs organ systems
What is an enzyme?
A biological catalyst
What do enzymes control?
All the reactions in a cell
What does a catalyst do?
Speeds up a reaction without being used up or changing the reaction
What are enzymes made of?
proteins (chains of amino acids)
What is a substrate?
A molecule that is changed in a reaction
What is an active sight?
A part of the enzyme where the substrate joins on to the enzyme
What kind of model shows an enzyme working?
the ‘lock and key’ model
When the substrate enters the active sight, what is it then called?
A substrate complex
What two factors affect the rate of enzymes?
pH
temperature
In an enzyme.. a higher temperature means..
an increased rate of reaction
What happens when the temperature of an enzyme is too hot?
Some of the bonds holding the enzymes together will break
This makes the enzyme lose its shape
The active sight no longer fits the substrate
The enzyme is DENATURED
What is the optimum temperature for human enzymes?
37 degrees
What is the process of cells breaking down small food molecules to release stored energy?
cellular respiration
What is the equation for aerobic respiration?
Glucose + Oxygen = Carbon Dioxide + Water (+ Energy)
C6H12O6 + 6O2 = 6CO2 + 6H2O (+ Energy)
What do cells use aerobic respiration for?
Use oxygen to oxidise food
What is it called when cells have to respire with no oxygen?
anearobic respiration
When does anaerobic respiration take place?
In muscle cells when they are working hard during excersize
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration
What are diffusion rates affected by?
concentration
temperature
available surface area
Where does diffusion happen?
In both liquids and gases
Diffusion is passive… What does this mean?
It takes place down a concentration gradient and does not use energy
What is Osmosis?
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
Name an example of a partially permeable membrane
A cell membrane
In osmosis there is a steady…
net flow
If a cell is short of water, the solution inside will become…
quite concentrated
Why does a cell short of water become concentrated?
So water can move into the cell by osmosis
If a cell has lots of water, the solution inside it will become…
more dilute
Are plants single celled or multi-cellular?
multi-cellular
What do plants store carbohydrate as?
Sucrose or starch
What are plant cell walls made up of?
cellulose
What do Animals store carbohydrate as?
Glycogen
What are vertebrates?
animals that have a backbone (vertebral column)
Name some invertibrates
sponges
molluscs
starfish
What do fungi feed off?
Other organisms
What are the two types of fungi?
Saprophytes
Parasites
Are fungi multi-cellular?
Yes but some are single celled
What are fungal cell walls made out of?
chitin
What are multi-cellular fungi made up of?
A mycelium
What is a mycelium
a tangled network of thread-like structures called hyphae
What is saprotrphic nutrition?
Where FUNGI secrete extracellular enzymes into the area outside their body, to dissolve their food (so they can absorb their nutrients)
Many fungi act as…
decomposers
What do fungi store carbohydrate as?
glycogen
Name 2 examples of fungi
Yeast - single celled
Mucor - multicellular
Can fungi photosynthesise?
no
Name two examples of protoctists
Chlorella (plant like)
Amoeba (animal-cell-like)
Are protoctists multi-cellular or single celled?
single celled
Name two examples of bacteria
Lacto-bacillus bulgaricus
Pneumococcus
Does bacteria cells have nuclei?
no
Can bacteria photosynthesise?
some can
What do bacteria feed off?
Other organisms
both living or dead
What can lactobacillus bulgaricus be used for?
makes milk go sour and turn into yoghurt
Name the organelles in a bacteria cell
Cell Wall Cytoplasm Cell Membrane Circular chromosome plasmids
What are plasmids?
extra bits of DNA
Name two organelles of a virus particle
Protein coat
DNA or RNA
Where so viruses reproduce?
inside living cells
What are organisms that depend on other organisms to live called?
parasites
Name two viruses and what they cause
- Influenza virus
causes flu - HIV
causes AIDS
What does Tobacco mosaic virus do?
makes the leaves of tobacco plants discoloured by stopping them from producing chloroplasts
Name the bacteria that causes pneumonia
Pneumococcus
What protoctist causes malaria?
Plasmodium
What is Active Transport?
the movement of particles against a concentration gradient, using energy released during respiration
What three factors affect diffusion, osmosis, and active transport?
Surface Area to Volume Ratio
Temperature
Concentration Gradient
When cells have a larger surface area to volume ratio…
The rate of diffusion , osmosis and active transport is higher
What does concentration not affect?
active transport
pepsin is an enzyme working in the stomach. What is its optimum pH?
pH 2
hydrochloric acid
what happens to the enzymes if the pH is too high/ too low?
the pH interferes with the bonds holding the enzyme together. This changes the shape of the active site and denatures the enzyme
what is the optimum pH for MOST enzymes?
neutral - pH 7
what is meant by the word ‘turgid’ to describe a plant cell?
when a plant is well watered, all its cells will draw water in by osmosis and become plump and swollen
what is the name for when, in a turgid cell, the contents of the cell start to push against the cell wall? why does this help the plant?
turgor pressure - helps support the plant tissues
what happens to plant cells if there’s no water in the soil?
the plant starts to wilt because the cells start to lose water and so lose their turgor pressure - they become FLACCID
why, even when a cell is flaccid, does it not completely lose its shape?
the inelastic cell wall keeps things in position
