Biology Y10 Cell Division and Cancer Flashcards
how do unicellular organisms work
one cell performs all the functions necessary to survive - can exchange directly with the environment
what functions are necessary to survive
- reproduction
- exchange with environment
- energy transfer (respiration)
- digestion
- support and structure
what are cells
the basic building blocks of all living things
what is a tissue
group of cells with a similar structure working together to perform a specific function
what is an organ
group of tissues working together to perform a specific function
what is an organ system
group of organs working together to perform a specific function
what is an organism
group of organ systems working together to perform all the functions necessary to survive
how do multicellular organisms work
ccells become specialised to perform specific functions and cells with similar functions group together to make tissues
what organelles does a generic animal cell have
- cytoplasm
- mitochondria
- ribosomes
- cell membrane
- nucleus
what organelles does a generic plant cell have
- cytoplasm
- mitochondria
- ribosomes
- cell membrane
- nucleus
- vacuole
- chloroplasts
- cell wall
function of cytoplasm
site of most chemical reactions
function of mitochondria
site of aerobic respiration
function of ribosomes
site of proteinsynthesis
function of cell membraane
controls what goes in and out of the cell
function of nucleus
stores DNA and controls functions of cell
function of vacuole
stores energy for when it is needed
function of chloroplasts
site of photosynthesis
why are plants green
because chloroplasts have chlorophyll which is green
function of cell wall
keeps cell rigid
what is the cell wall made of
cellulose
what is a specialised cell
cell which has different features that give it the ability to do a certain function
function of nerve cell
carry electrical impulses around the body
location of nerve cell
nervous system (all over the body), but especially the spinal cord and brain
features of nerve cell
- dendrites - make connections to other cells
- axon - long - carries nerve impulses from one place to another
- synapses - transmitter chemicals passs impulses to other cells, have mitochondria to make transmitter chemicals
- myelin sheath - provides isulation so impulses don’t get lost
function of muscle cell
contract and relax to move the bones of the skeleton, so that vertebrates can move
location of muscle cell
muscle tissues
features of muscle cell
- mitochondria - transfer energy for chemical reactions
- can store glycogen
- contain special proteins to enable contraction
function of sperm cell
move through water/female reproductive system to reach egg and pass on genetic information
location of sperm cell
testis
features of sperm cell
- acrosome - stores digestive enzymes for breaking down outer layers of egg
- nucleus - contains genetic information to be passed on
- mitochondria - transfer energy needed for tail to work
- tail - whips from side to side to move
function of root hair cell
help take up water and mineral ions more efficiently
location of root hair cell
tips of growing roots close to xylem tissue
features of root hair cell
- root hair - increase surface area for water to come in
- large permanent vacuole - speeds up osmosis - maintains water potential gradient
- mitochondria - transfer energy needed for active transport of mineral ions
function of photosynthetic/palisade cell
carry out photosynthesis
location of photosynthetic/palisade cell
leaves and stem
features of photosynthetic/palisade cell
- large permanent vacuole - keeps cell rigid as a result of osmosis, form photosynthetic tissue to support stem
- chloroplasts - contain chlorophyll for photosynthesis
function of xylem cell
carry water and mineral ions from the roots to leaves and shoots, supports plant
location of xylem cell
all through the plant
features of xylem cell
- lignin spiral - strong - withstands pressure, impermeable
- hollow tube of xylem - allow water and mineral ions to easily move through
- dead cells - no organelles or cytoplasm
function of phloem cell
carry food made from photosynthesis (dissolved sugars and amino acids) around the body of the plant
location of phloem cell
all through the plant
features of phloem cell
- phloem vessel and sieve plates - allow water with dissolved food to move freely up and down
- companion cells - support to keep cells alive
- mitochondria - transfer energy to move dissolved food, allow active transport
- alive, but without internal structures
what directions are xylem and phloem
xylem - unidirectional, phlom - bidirectional
what are chromosomes made of
DNA
how many chromosomes do humans have and from where
23 pairs - 23 from mother, 23 from father
what is a gene
a small section of DNA that determines characteristics
how do organisms grow
through cell division
what does cell division produce
2 identical daughter cells
why is cell division needed
- growth
- development
- replacement
what is apoptosis
controllde cell death (killing cells that are old or damaged)
describe the cell cycle and what are the major stages
(0. temporary resting phase)
1. DNA replicates to form 2 copies of each chromosome
2. cell grows and makes more organelles
3. chromosomes line up in middle then pulled 1 set to each side
4. nucleus divides
5. cytoplasm and cell membrane divide to form 2 identical daughter cells
0, 1, 2 - stage 1
3, 4 - stage 2 (mitosis)
5 - stage 3 (cell division)
what are tumours
abnormal and uncontrolled cell growths caused by mutations
features of benign tumours
- contained in one place (usually a membrane)
- don’t spread
- can put pressure on or damage tissues and organs (can be life-threatening)
- slow growing
- non-cancerous
features of malignant tumours
- not enclosed
- can spread to other parts of the body (via blood or lymph)
- disrupt function of normal tissues
- fast growing
- cancerous
what forms when malignant tumours spread
secondary tumours or metastases
what causes cancer
lifestyle:
* UV rays
* smoking
* obesity
viruses:
* HPV
genes:
* faulty BRCA gene
carcinogens:
* asbestos
* excess alcohol
what are stem cells
unspecialised cells that have the potential to become any type of cell
what happens during the first few days after fertilisation
stem cells divide to form more stem cells
what happens about five days after fertilisation
stem cells differentiate
what is differentiation
developing structural differnces which enable cells to carry out a specific function
is differentiation reversible
animal cells - no
most plant cells - yes
why can stem cells divide
they have access to all genes
how do most cells replace themselves
cell division
what are tissue-specific/somatic stem cells
sten cells which can only divide to form one type of tissue
why cantissue-specific/somatic stem cells divide
most genes are still switched on (but not all)
where do undifferentiated cells form in plants
at meristems (roots and shoots)
when do plant stem cells fully differentiate
when they are in their final position in the plant
what happens when there are dysfunctional or damaged cells that can’t repair themselves
can cause health problems
describe therapeutic cloning
- isolate nucleus from somatic stem cell
- isolate egg cell from donor
- insert nucleus into egg
- divides to form embryo
- after ~5 days, forms a blastocyst
- stem cells removed and cultured into specialised cells needed by patient
what are risks with therapeutic cloning
if embryo is donated, there is risk of rejection or lifelong need for immunosuppresants
what are issues with stem cells (therapeutic cloning)
- hard to find donor
- could be considered destroying life
- patient could be exploited
what are the methods of cancer treatment
- surgery
- radiotherapy
- chemotherapy
- immunotherapy
