Biology 5 Flashcards
What 5 things are in a human cell ?
Nucleus Cytoplasm Cell Membrane Mitochondria Ribosomes
What are all living things made of ?
Cells
What is inside the nucleus ?
Genetic information that controls the activities of a cell
What is cytoplasm ?
A gel like substance where most of the chemical reactions take place. Enzymes control these reactions
What is the job of the cell membrane ?
Holds the cell together, controlling what goes in and out
Where does respiration take place ?
In mitochondria
What does a ribosome make ?
Proteins
What three things are in plant cells and not in animal cells ?
Cell wall
Vacuole
Chloroplasts
Why do plants have cell walls ?
It supports the cell and strengthens it
What is vacuole ?
A weak solution of sugar and salts (cell sap)
Where does photosynthesis occur ?
In the chloroplasts, which contain chlorophyll
Name a single celled organism ?
Yeast
Give an example of a cell without a nucleus
Bacteria - their genetic information floats in the cytoplasm
What is diffusion ?
the SPREADING OUT of PARTICLES from an area of HIGH concentration to an area of LOW concentration
Where does diffusion happen and why ?
Solutions and gases because the particles are free to move about randomly
Describe how perfume diffuses through the air in a room
The perfume particles are in high concentration when sprayed but it then diffuses around the room as perfume particles are in low concentration there
How do cell membranes restrict what comes in and goes out of a cell ?
Dissolved substances can move in an out of cells by diffusion. However small molecules are the only ones that can fit in, so large molecules that are unwanted cannot get in
What is special about a palisade leaf cell ?
It has more chloroplasts for photosynthesis. They have a tall shape that increases surface area to absorb more CO2
What are red blood cells adapted to do ?
Carry oxygen
What is the shape of a red blood cell ? How does this benefit it ?
Concave - giving it a bigger surface area for absorbing oxygen
Other than its shape, name two adaptations of a red blood cell
- Packed with haemaglobin
* no nucleus so that there is more room for the haemaglobin
What cells are specialised for reproduction ?
Sperm and Egg cells
What is the main function of an egg cell ?
To carry DNA and contain huge food reserves to nourish a developing embryo
How does an egg make sure only one sperm fertilises it ?
It’s membrane changes instantly
How does a sperm cell get the male DNA to the female ?
It has a long tail and streamlined head that helps it to swim to the egg, there’s a lot of mitochondria to supply energy
What is the process by which cells become specialised ?
Differentiation
What do large multicellular organisms have ?
Organ systems
What do these different organ systems do ?
Exchange and transport materials
What is a tissue ?
A group of cells, that can include more than one type of cell, that carry out a specific function
What is an organ ?
A group of different tissues that work together to perform a certain function
What is the equation for photosynthesis ?
Carbon dioxide + water
——>
Glucose + oxygen
Where does photosynthesis happen ?
In the chloroplasts
What does chlorophyll do ?
Absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose
What is the by-product of photosynthesis ?
Oxygen
In what part of the plant does photosynthesis occur ?
In the leaves
What are three main factors that affect the rate of photosynthesis ?
Light intensity, volume of CO2 and the temperature
Why is water not a main factor affecting the rate of photosynthesis ?
When a plant is so short of water that it becomes a limiting factor, the plant is already in trouble that photosynthesis doesn’t matter
Describe how light intensity increases the rate of photosynthesis
As the light intensity increase so does the ROP (rate of photosynthesis) up to a certain point. Then another factor is affecting ROP. The same goes for CO2
What happens if the temperature is too high ?
Enzymes in the plant denature
At what temperature do enzymes denature ?
Around 45 degrees centigrade
What is the most common way to artificially create an ideal environment for plants to grow ?
Using a greenhouse
How can a gardener regulate heat in a greenhouse ?
In winter a heater can be used, in summer vents and shades can be used incase it gets too hot
Why do some gardeners use artificial light ?
So that plants can grow even when the sun has gone down
How can you increase the level of carbon dioxide in a greenhouse ?
A paraffin heater, it releases CO2 as a by-product
Plants use glucose for 5 things, what are they ?
- For Respiration
- Making Cell Walls
- Making Proteins
- Stored in Seeds
- Stored as Starch
What is glucose converted into to make cell walls ?
Cellulose
How are proteins made in plants ?
Glucose is combine with nitrate ions from soil to make amino acids. These are then made into proteins
What are glucose turned into when stored in seeds ?
Lipids (fats and oils)
Why is it better to store starch rather than glucose ?
Starch is insoluble, a cell with lots of glucose would attract water and swell
What is an organ system ?
A group of organs working together to form a particular function an example is the digestive system
What is a quadrat ?
A square frame enclosing a known area which allow us to compare an organism distribution
What does a transect do ?
It helps you I find out the distribution of an organism along a line
How is something reliable ?
When it is reproducible an repeatable
How can you make your results more reliable ?
- Increase sample size by using as many transects and quadrants as possible
- Use random samples
How do guard cells allow water out of the leaf ?
They open and close the stomata which are pores
What happens to the stomata when there is lots of water in the plant ?
They become turgid and opens the stomata so gases can enter the leaf and photosynthesis can take place
What happens when a plant I short of water ?
The guard cells become flaccid and cause the stomata to close. This stops too much water escaping
