B1-Cell Biology

Created by

Elle Roberts

Cards (46)

examples of eukaryotic cells
animal and plant cells
examples of prokaryotic cells
bacteria
structures of an animal cell
nucleus
cytoplasm
cell membrane
mitochondria
ribosomes
structures of a plant cell
nucleus
cytoplasm
cell membrane
cell wall
mitochondria
ribosomes
permanent vacuole
chloroplasts
structures of a bacteria cell
cell membrane
cell wall
plasmids
cytoplasm
singular strand of DNA
why are electron microscopes better?
higher magnification
higher resolution
see smaller structures in more detail
what is the formula for magnification?
magnification = image / actual
what is cell differentiation?
a cell changes to become specialised for its job
what are sperm cells specialised for?
reproduction
-has a long tail and a streamlined head for swimming to the egg
-lots of mitochondria for energy to swim
-enzymes in the head to digest through the egg cell membrane
what are nerve cells specialised for?
rapid signalling
-long and have branched connections to connect to other nerve cells and form a network through the body
what are muscle cells specialised for?
contraction
-long and contain lots of mitochondria for energy needed for contraction
what are root hair cells specialised for?
absorbing water and minerals
-gives the plant a big surface area
what is the phloem specialised for?
transports food round the plant
-very few subcellular structures so stuff can flow through
what is the xylem specialised for?
transports water round the plant
-hollow in the centre for water to flow through
what are chromosomes?
coiled up lengths of DNA molecules
what do genes control?
the development of different characteristics
how many chromosomes does each human have?
23 pairs
what are the steps in growth and DNA replication?
-DNA is in long strands
-cell grows and mitochondria and ribosomes are increased
-DNA is duplicated to make X shaped chromosomes
what are the steps of mitosis?
-chromosomes line up at the centre of the cell and are pulled apart. Each arm of the chromosomes go to opposite ends of the cell
-membranes form around the sets of chromosomes
-nucleus divides
-cytoplasm and cell membrane divide
-produces two genetically identical daughter cells
what are stem cells?
undifferentiated cells that can differentiate into any type of cell
where are stem cells found?
human embryos - any type of cell
adult bone marrow - certain type of cell
what can adult stem cells be used for?
cure disease - can replace faulty blood cells
what can embryonic stem cells be used for?
replace faulty cells - make insulin producing cells for diabetics
make nerve cells for people paralysed by spinal injuries
what is therapeutic cloning?
embryo can be made to have the same genetic info as the patient so wouldn't reject the stem cell
arguments against stem cells
-unethical as it kills a potential life
-stem cells grown in labs can be contaminated and passed on
arguments for stem cells
-curing patients of suffering is more important than rights of an embryo
-the embryos used are unwanted and would be destroyed
-resolve injuries and disease
where are stem cells found in plants?
meristem
what can plant stem cells be used for?
-produce clones of plants cheap and quickly
-grow more plants of rare species to prevent extinction
-grow crops of identical plants that have desired features (disease resistance)
what is diffusion?
spreading out of particles from an area of higher concentration to an area of lower concentration
how does a concentration gradient affect diffusion?
the bigger concentration gradient, the faster the diffusion rate
how does temperature affect diffusion?
a higher temperature gives a faster diffusion rate because the particles have more energy so move faster
what do cell membranes do?
let substances in and out by diffusion
what substances can diffuse through a cell membrane?
oxygen
glucose
amino acids
water
what is osmosis?
movement of water molecules across a partially permeable membrane from a region higher water concentration to a region of lower water concentration
what is active transport?
substances absorbed against a concentration gradient using energy from a lower concentration to a higher concentration
how is active transport used in plants?
through root hair cells for the uptake of minerals and water
how are exchange surfaces adapted?
-thin membrane for a smaller diffusion distance
-large surface area so lots of substances can diffuse at once
-lots of blood vessels in animals to get things in and out of blood quickly
-in animals gas exchange surfaces are ventilated
what is the job of the lungs?
transfer oxygen to blood and remove waste carbon dioxide
what do alveoli do?
maximise diffusion of oxygen and carbon dioxide
what are adaptations of alveoli?
-enormous surface area
-moist lining for gases
-very thin walls
-a good blood supply