cell biology

Created by

Iris

Cards (44)

what is differentiation
the process by which a cell becomes specialised for its function
when does an organism have the ability to differentiate(period of life)
animals: early stages for development
plants: always
what are undifferentiated cells called
stem cells
what is the function of a sperm cell
get male DNA to female DNA
how are sperm cells specialised for their function
long tail and streamlined head to swim
lots of mitochondria for energy
carries enzymes in order to digest through egg cell membrane
what is a nerve cells function
carry electrical signals from one part of the body to another
how are nerve cells specialised
long to cover more distance
branched connections to connect to other nerve cells to form a network throughout body
what is a muscle cells function
contract quickly
how are muscle cells specialised for their function
long for space to contract
lots of mitochondria for engery
what is a root hair cells function
absorb water and minerals
how are root hair cells specialised for their function
big surface area for maximum absorption
what is a xylems function
transport water and mineral ions upwards
how is a xylem specialised for its function
hollow so uninterrupted flow
lignin in cell wall to strengthen to withstand high pressure
what is the function of a phloem
transport sugars bidirectionally
how is a phloem specialised for its function
mitochondria in companion cells to pump sugars
what are matching pairs of chromosomes called
homologous chromosomes
how many chromosomes and chromosome pairs does a human have
chromosomes: 46
pairs: 23
put these in order of biggest to smallest: nucleus, gene, chromosome, cell, DNA
cell, nucleus, chromosome, DNA, gene
how many chromosomes are in an egg/sperm cell
23
what are the 4 bases of DNA
adenine, thymine, guanine, cytosine
how do the bases pair up
weak hydrogen bonds
what is DNA
chemical that genetic material is made from
what is a gene
small section of DNA that codes for a specific protein
what does a chromosome do
carries all genetic information in an organism
what is the shape of DNA called
double helix
what is mitosis
cell division
what is mitosis needed for
growth + repair
what are the stages of mitosis
1.original cell increases in size+mass and duplicates its DNA and subcellular structures, forming x-shaped chromosomes
2.chromosomes line up across the middle and spindle fibres separate them to poles of the cell equally
3.new nuclear membrane forms, splitting the cell into two new identical daughter cells
what is active transport
molecules moving across a partially permeable membrane from an area of low concentration to an area of high concentration using carrier cells
what is osmosis
water molecules passively moving across a partially permeable membrane from an area of high concentration to an area of low concentration
what is diffusion
particles spreading out from an area of high concentration to an area of low concentration
what increases the rate of diffusion
high temperature as more energy to move faster and bigger concentration gradient
what can pass through a partially permeable membrane
small molecules only
where can we get stem cells from
embryos at first stage, adult bone marrow, meristem in plants, umbilical chord
name 3 things we can use stem cells to treatin humans
paralysis, burns, heart disease
why are embryonic stem cells more usefulthan adult bone marrow stem cells
embryonic = pluripotent, low chance of rejection
adult = bipotent, high chance of rejection
why might people opt for adult bone marrow stem cells over embryonic stem cells
death of embryo, no consent from embryo
how can we prevent stem cell rejection
make an embryo have the same genetic information as the patient
why can substances diffuse directly into a single-celled organism
large surface area to volume ratio
why do multicellular organisms need an exchange surface
small surface area to volume ratio