Chapter One - Cells Flashcards
Function of a cell wall
Rigid structure providing structural integrity - fully permeable
Function of cytoplasm
Site of chemical reaction, jelly-like fluid
Function of a nucleus
Contains genetic information in the form of chromosomes
Function of nuclear membrane
Surrounds nucleus
Function of chloroplast
Site of photosynthesis,contains chlorophyll
Function of a permanent vacuole
Storage of salts and sugars and provides turgor
Label an animal cell
- cell membrane
- Cytoplasm
- nuclear membrane
- chromosomes
Label a plant cell
- cell membrane
- cytoplasm
- chloroplast
- nuclear membrane
- chromosomes
- vacuole
- cellulose cell wall
Label a bacterial cell
- plasmid
- loop of DNA
- cytoplasm
- non-cellulose cell wall
Cell structure exam tips
- plant and animal cells are much larger than bacterial cells
- plant cells tend to have a regular shape because of their cell walls
- bacterial cells contain a large loop of DNA in addition to many small rings of DNA called plasmids.
Equation to work out actual size from a magnification
Action size = observed size / (divided by) magnification
Equation for magnification
Magnification = observed size / actual size
Function of a cell membrane
Controls entry and exit of substances - selectively permeable
Levels of organisation
Cell - tissue - organ - organ system - organism
Explain the process of growth in animals compared to plants
Animal growth involves growth all over their bodies whereas plants tend to grow only at the tips of their roots and shoots (apices)
Explain growth in plants
Plants grow only at the tips of their roots and shoots (apices). The reason for this is only certain areas of the plant have the ability to grow. These areas are called meristem. Meristematic tissues are made up of unspecialised cells that have the ability to become any type of plant cell. Plants have these cells for the duration of their life. This is why gardeners can take cuttings (a selected section cut from a plant) and grow whole new plants from the cuttings.
Three major sources of stem cells
- umbilical cord blood
- embryos
- adult cells
Why is stem cell research considered controversial?
Some groups believe that the types of procedures used to harvest stem cells are controversial as life can be created artificially. Others have concerns that people seek to have so-called ‘designer babies’. For example, in order to provide stem cells for the treatment of illnesses in other family members.
What is the use of stem cells being investigated for?
A way of producing meat in a cheaper and more efficient way. It is possible to grow muscle tissue from a cow, pig or chicken which could then be used as a food source. It is hoped that this would be cheaper as the costs of feeding and keeping animals would be greatly reduced.
Exam tip on stem cell research
It is important to keep your answer balanced, consider both the positive and negative arguments.
Definition of diffusion?
Diffusion is the random molecular movement of molecules from a region of high concentration to a region of lower concentration along a concentration gradient.
How can diffusion be demonstrated?
A sugar solution in visking tubing immersed in a beaker of water.
Why is diffusion important for photosynthesis?
Diffusion is important in the movement of gases into and out of leaves.
