extra Flashcards
(15 cards)
NUCLEUS
Largest organelle
Controls the activities of the cell
Contains chromosomes
Chromosomes carry genes
The genes determine which proteins ** the cell can make
CELL MEMBRANE
Forms a boundary between the cytoplasm and the outside of the cell
Some chemicals can pass through this barrier and the cell can control what comes in and out.
It is selectively permeable
e.g. oxygen goes in, CO2 goes out
CYTOPLASM
jelly-like substance which contains all of the organelles (e.g. nucleus and mitochondria)
Many of the cell’s chemical reactions take place in the cytoplasm
These are called metabolic reactions.
MITOCHONDRIA
Carry out some of the reactions of respiration
Therefore releasing energy for the cell (in the form of ATP)
Cells that have a high demand for energy usually have many mitochondria, such as muscle cells.
CELL WALL
Found only in plant cells
It is made of a non-living material called cellulose
Helps the cell keep its shape
It is freely permeable
CHLOROPLAST
Found in some plant cells
Contains chlorophyll
Chlorophyll is a green pigment
It absorbs light energy to make food in the process of photosynthesis
VACUOLE
Found only in plant cells
Filled with cell sap
Cell sap is a store of dissolved sugars, mineral ions and other solutes
Helps keep the cell’s shape
aerobic respiration
glucose + oxygen –> carbon dioxide + water + energy
C6H1206 + 6O2 –> 6CO2 + 6H20
anaerobic
glucose –> ethanol + carbon dioxide (+ some energy)
glucose –> lactic acid + some energy
diffusion
is the net movement of particles from an area of high concentration to an area of low concentration
osmosis
is the net movement of water particles from an area of high concentration to an area of low concentration through a partially permeable membrane
active transport
is the movement of substances against a concentration gradient using energy from respiration
stem cells
a stem cell is a cell that has the ability to divide many times by mitosis while remaining undifferentiated
embryonic stem cell: found in the early stage of development of the embryo, can differentiate into any type of cell
adult stem cell: found in certain adult tissues, have lost the ability to differentiate into any type of cell
many ppl object morally to using embryos for medical purposes.
rate of diffusion affected by
concentration gradient happens more quickly with steep
surface area to volume ratio
the distance
the temperature
diabetes
some people have a disease where their pancreas cannot make enough insulin to keep their blood glucose level constant - rises to very high concentrations
symptom glucose in urin
constant thirst
type 1 diabets genetic
limit carbohydrates, receive daily injections of insulin to keep blood glucose at the right level
type 2 overweight poor diet, resistance to insulin
prevented eating a good diet, regular exercise
