cell biology Flashcards
what is the order of cell size?
- cell
- tissue
- organ
- organ system
- organism
what does an animal cell contain?
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Ribosomes
what does a plant cell contain?
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Ribosomes
- Cell wall
- Permanent vacuole
- Chloroplasts
what is the nucleus?
contains genetic material, controls the activities of the cell
what is the cytoplasm?
gel like substance where most of the chemical reactions happen. It contains enzymes that control the reactions
what is the cell membrane?
holds the cell together and controls what goes in and out the cell
what is the mitochondria?
these are where most of the aerobic respiration take place
what are the ribosomes?
these are where proteins are made in the cell
what is the cell wall?
made of cellulose, supports and strengthens the cell
what are the chloroplasts?
these are where photosynthesis occurs, contains chlorophyll which absorbs the light needed for photosynthesis.
what is the vacuole?
stores water to keep the plant turgid (firm)
what do prokaryotic cells contain?
note: prokaryotic cells use binary fission for cell division
- cytoplasm
- cell membrane
- cell wall
- singular circular - strand of DNA
- plasmids (small rings of DNA)
Give an example of a prokaryotic cell:
bacterial cell
what do eukaryotic cells contain?
note: eukaryotic cells use mitosis for cell division
- cell membrane
- cell wall (sometimes)
- cytoplasm
- ribosomes
- chloroplasts
- mitochondria
- nucleus
Give an example of an eukaryotic cell:
Plant cells or animal cells
how to calculate magnification?
magnification = image size/real size
name some specialized cells:
1) sperm cells - reproduction
2) nerve cells - rapid signaling
3) muscle cells - contraction
4) root hair cells - absorbing water and minerals
5) phloem/xylem - transporting substances in plants
what are chromosomes?
chromosomes contain genetic material, They are coiled up pieces of DNA molecules, each chromosome contains a large number of genes.
describe growth & DNA replication:
- in a cell that is dividing, the DNA is spread out in long strings
- the cell has to grow and increase the amount of subcellular structures such as mitochondria and ribosomes
- it then duplicates its DNA - one copy for each new cell
- the DNA is copied and forms X shaped chromosomes.
describe the process of Mitosis:
- the chromosomes line up at the centre of the cell and cell fibres pull them apart.
- The two arms of each chromosomes go to opposite ends of the cell
membranes form around each of the sets of chromosomes. - These become the nuclei of the new cells. the nucleus has split.
- lastly, the cytoplasm and cell membrane divide
- the cell has now produced 2 daughter cells, which are identical.
Describe the process of binary fission:
- prokaryotic cells replicate using binary fission
- the circular DNA and plasmids replicate
- the cell gets bigger and the strands move to opposite poles of the cell
- the cytoplasm begins to divide and new cell walls form
- the cytoplasm divides and two daughter cells are produced
- each cell has one copy of the circular DNA but they can have a variable number of copies of the plasmid(s)
Describe stem cells:
- embryonic stem cells can turn into any type of cell
- stem cells may be able to cure many diseases
- some people are against stem cell research
- stem cells can produce identical plants
give a reason for stem cell transplants:
- can be used to replace faulty cells
- in a type of cloning, therapeutic cloning, an embryo could be made to have the same genetic information as the patient (cannot be rejected)
give a reason against stem cell transplants:
- they feel the human embryos shouldn’t be used as it is a potential human life
- it provides a health risk to everyone involved
- It isn’t cheap and we don’t know the long term affects
how are stem cells used to produce plant cells?
- stem cells are in the meristems (Where growth occurs)
- during the plant’s life, cells in the meristem tissues can change into any type of plant cell
- they can be used to grow more plants of rare species
- can also be used to grow crops with specific features for farmers
What is diffusion?
Diffusion is the SPREADING OUT of particles from an area of HIGHER concentration to an area of LOWER concentration
what is osmosis?
osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
What is active transport?
Active transport is when a substance needs to be absorbed against a concentration gradient.
what happens during gas exchange in the lungs?
- the lungs transfer oxygen to the blood and remove waste carbon dioxide from it
- to do this, the lungs contain millions of little air sacs (Alveoli) where gas exchange takes place
Give another example of exchanging substances:
- the villi provide a really big surface area inside the small intestine.
- They increase the surface area so that digested food is absorbed more quickly
- The structure of leaves lets gases diffuse in and out of cells
- Gills have a large surface area for gas exchange
