AQA BIOLOGY

Created by

Tammam Elmahdawi

Cards (109)

In which type of cell would you find a cell wall, chloroplasts and a vacuole?
plant cell
What does an animal cell have?
- cytoplasm
- nucleus
- ribosomes
- cell membrane
- mitochondria
What does the nucleus do?
contains genetic material that controls the activities of the cell
What is the cytoplasm?
gel-like substance where most of the chemical reactions happen. It contains enzymes which control these chemical reactions
What is the cell membrane 
holds the cell together and controls what goes in and out
What happens in the mitochondria? 
these are where most of the reactions for respiration take place. Respiration releases energy that the cell needs to work
What happens in the ribosomes?
these are where proteins are made in the cell
What does a bacterial cell NOT have?
a nucleus- genetic material floats in the cytoplasm
What is a yeast cell an example of?
a single cell organism
What does a yeast cell have? 
- nucleus
- cytoplasm
- cell membrane
- surrounding cell wall
How is a leaf cell different from a yeast cell?
leaf cells have chloroplasts and a cellulose cell wall. yeast cells have neither
What is the definition of diffusion? 
the SPREADING OUT of PARTICLES from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION
or
the NET MOVEMENT of PARTICLES down a CONCENTRATION GRADIENT
What substances can diffuse through cell membranes?
small molecules like oxygen, glucose, amino acids and water
What substances can't diffuse through cell membranes?
big molecules like starch and proteins
What are some examples of diffusion? 
- the diffusion of oxygen into the cells of the body from the bloodstream as the cells are respiring (and using up oxygen)

- the diffusion of carbon dioxide into actively photosynthesising plant cells

- the diffusion of simple sugars and amino acids for the gut through cell membranes
When, and in which direction, will diffusion take place in solutions and in gases? 
- if two solutions are separated by a cell membrane, particles will move from a region of high concentration to a region of low concentration

- gases will also diffuse through the air from a region of high concentration to a region of low concentration
How is a leaf cell adapted to carry out photosynthesis?
- the leaf has mesophyll tissue
- the mesophyll cells contain chloroplasts which can photosynthesise
How are palisade cells adapted for photosynthesis?
- packed will chloroplasts for photosynthesis
- tall shape means a lot of surface area exposed down the side for absorbing carbon dioxide from the air in the leaf
- they are grouped together at the top of the leaf so that they can absorb more sunlight
How are red blood cells adapted to carry oxygen?
- concave shape gives a big surface area for absorbing oxygen. it also helps them pass smoothly through capillaries to reach body cells
- packed with haemoglobin which absorbs oxygen
- they have no nucleus to leave even more room for haemoglobin
How are sperm cells adapted for swimming to the egg? 
- streamlined head and flagella to help it swim to the egg
- there are a lot of mitochondria in the cell to provide the energy needed
- carry enzymes in their heads to digest through the egg cell membrane
If a cell has many mitochondria... 
it must need a lot of energy, e.g. muscle cell, sperm cell
If a cell has many ribosomes...
it is making a lot of protein, e.g. gland cells which produce enzymes
If a cell has flagella..
it must be able to move, e.g. sperm cells
What is the process by which cells become specialised?
differentiation
What is meant by the term differentiation of cells?
- when cells start to divide they are very similar
- as the tissues develop the cells change to form particular function
What is a tissue?
a group of similar cells that work together to carry out a particular function
What sort of tissue can you find in mammals?
- Epithelial tissue: covers some parts of the body, e.g. the inside and outside of the gut

- Muscular tissue: contracts to move whatever its attached to

- Glandular tissue: makes and secretes chemicals like hormones and enzymes
What is an organ? 
a group of different tissues that work together to perform a certain function, e.g. stomach
What tissues are the stomach made up of and what are their purposes?
- Epithelial tissue: covers the inside and outside of the stomach

- Muscular tissue: contracts the stomach wall to churn up the food

- Glandular tissue: produces digestive juices to digest food
What is an organ system? 
a group of organs working together to perform a particular function, e.g. the digestive system breaks down food
What organs does the digestive system include?
- glands
- the stomach
- the liver
- the small intestine
-the large intestine
What two glands produce digestive juices?
pancreas and salivary glands
what does both the stomach and small intestine do?
digest food
What does the liver do? 
produces bile
What does the small intestine do?
absorbs soluble food molecules
What does the large intestine do?
absorbs water from undigested food leaving faeces
Describe in detail what happens to food as it passes through the digestive system?
- the insoluble food is mixed with digestive juices produces by glands
- it is digested in the stomach and small intestine
- bile produced by the liver is added to the food to help digestion
- absorption of the soluble food takes place in the small intestine
- water is absorbed by the large intestineSee an expert-written answer!We have an expert-written solution to this problem!
What are the plant organs?
stems, leaves and roots
What are the tissues found in plants?
-Mesophyll tissue- where most of the photosynthesis occurs in the plant

- Xylem and Phloem- transport things like water, mineral ions and sucrose around the plant

- Epidermal tissue- this covers the whole plant
What is photosynthesis? 
the process that produces 'food' in plants and algae. the 'food' it produces is glucose