Topic 1-cells Flashcards
what are eukaryotic cells - two examples
complex cells like plant and animal cells
what are prokaryotic cells and an example
these are simpler smaller cells like bacteria
what are eukaryotes
organisms made of eukaryotic cells
what are prokaryotes
a single celled organism
what subcellular structures do most animal cells have
nucleus cytoplasm cell membrane mitochondria ribosomes
what subcellular structures does a plant cell have
nucleus cytoplasm cell membrane mitochondria ribosomes cell wall vacuole chloroplasts
what does the nucleus do
contains the genetic material and controls cell activity
what does cytoplasm do
chemical reactions
what does the cytoplasm have and what for
enzymes to control reactions
what does the cell membrane do
holds cell together and controls what goes in and out
what does mitochondria do
reactions for aerobic respiration take place
what do the ribosomes do
where proteins are made
what does the cell wall do and what is it made of
made of cellulose and holds cell together
what does the vacuole do
contains cell sap - sugar and salt solution
what does the chloroplasts do and what do they contain and what for
where photosynthesis occurs making food for the plant it contains chlorophyll which is a green substance that absorbs light for photosynthesis
what five things are in a bacterial cell
cytoplasm cell membrane cell walk strand of DNA small rings if DNA - plasmids
what happens to a cell to make it become specialised
differentiation
what is a cell before it differentiates
stem cell
where would you find stem cells in an adult
bone marrow
how limited are adult stem cells to differentiate
they are MULTIPOTENT they can differentiate into a small number of cells
where else can stem cells be found
enbryo
how limited are embryonic stem cells to differentiate
they are PLURIPOTENT and can become almost any type of cell
what are plant stem cells called
meristem
where are meristem cells found
parts of a plant that grow
how able are meristem able to differentiate
they retain their ability to differentiate and are not as limited as adult stem cells
why are meristem useful
make quick cheap clones of a plant
help save rare plants
why are people against embryonic stem cell research to replace faulty cells
religion
childs life
disruption of development
a human life in embryonic stage
concerns of methods
some people see it as murder
why are some people for the use of embryonic stem cell research
helps replace faulty cells
could get rid of some diseases/ illnesses
it would be an unwanted embryo and would have been destroyed anyway
help burn victims
can test drugs on them instead of animals
what is the function of a sperm cell - specialised cell
to swim to and fertilise an egg cell
what are the adaptations of a sperm cell that help it carry out its function -5
- mitochondria for energy to swim
- long tail to swim
- enzymes break down wall of egg
- nucleus for DNA for fertilisation
- pointed head to burrow
what is the function of a muscle cell
- contraction
movement
what are the adaptations of a muscle cell-3
can contract and relax -movement
connected to nerve cells
mitochondria for energy
fibres
what is the function of a nerve cell
fast signalling
how are nerve cells adapted-3
myelin sheath- speeds electrical impulses
dendrites- recieve neurotransmitters
axon- carries impulse
what is the function of a palisade cell
absorb sunlight for photosynthesis
what are the adaptations of a palisade cell -2
chloroplasts
long and flat for a large surface area
what is the function of a root hair cell
absorb water and minerals
what are the adaptations of a root hair cell - 3
cell membrane- controls in and out
perméable
extension increases surface area
what is the function of xylem and phloem
to transport water and sugars
how is xylem adapted
is hollow water can easily flow
how is phylem adapted
not many subcellular structures sugars can flow through easily
what is a isotonic cell
same water to cytoplasm concentration
what is a hypertonic cell
less water concentration to cytoplasm
what is a hypotonic cell
more water than cytoplasm concentration
what is a gene
a short sequence of dna that codes for a specific protein
what is DNA short for
deoxyribose nucleic acid
what are chromosomes
coiled up lengths of DNA
how many pairs of chromosomes does each nucleus have
23 pairs
how many chromosomes in total
46
how many of each gametes
23-egg
23-sperm
why do cells need to replicate
for growth and repair
what are the four stages of the cell cycle
G1
S
G2
M
what happens in G1 phase
growth
what happens in S
DNA synthesis
what happens in G2
growth and preparation for mitosis
what happens in M
cell devision or mitosis
what are the five stages of mitosis
1-genetic information copied
2-chromosomes line up in the middle of the nucleus
3-cell and chromosomes start to split
4-they are pulled appart by spindle fibres
5-two separate daughter cells genetically the same appear
what is binary fission
prokaryotic cells replication- replication of bacteria cells
what happens in binary fissions -4
1- plasmids and circular DNA replicate
2- cell gets bigger and plasmids and strands move to opposite poles lf the cell
3- cytoplasm begins to divide and new cell wall form
4- cytoplasm divides and two daughter cells are produced
what does each binary fission daughter cell have
one copy of circular DNA and varied number of plasmids
what is diffusion
diffusion is the spreading out of particles from an area of high concentration to an area of low concentration
how can you increase the rate of diffusion
increase the concentration gradient because the bigger the concentration gradient the faster the rate of diffusion
a higher temperature give the particles more kinetic energy
what sort of membrane does diffusion occur over
a partially permeable membrane
what sort and size molecules can diffuse over the membrane
small molecules like oxygen and glucose and amino acids and water can fit through
big like starch and proteins cant get through
what is osmosis
osmosis is the movement of water molecules across a partially permable membrane from a region of high water concentration to a region of low water concentration
what is active transport
active transport is when something needs to be absorbed against the concentration gradient —
what does active transport require in the cell membranes
protein carriers
what three things affect the rate of diffusion
temp
concentration gradient
surface area
