Chapter 2 Cells Flashcards
Cell membrane (3 things)
● Made up of lipids and proteins
● Surrounds the cytoplasm of the cell → Contains the cytoplasm within the cell
● Partially permeable → Allows small-sized substances to pass through it, into and out
of the cell
Cytoplasm [1]
● Jelly-like substance containing organelles → site of many chemical reactions
Nucleus (2)
● Consists of nucleoplasm surrounded by nuclear envelope
● Contains chromatin (carries genetic materials) in one or more nucleoli → Controls
cell activities such as cell growth and repair of worn-out structures. Essential for cell
division.
Rough endoplasmic reticulum (2)
● Consists of a network of interconnected spaces lined with a membrane.
● Surface appears rough due to attached ribosomes → Transports proteins made by
attached ribosomes to the Golgi apparatus for secretion out of the cell
Ribosomes (3)
● Small round structures
● Either attached to the surface membrane of RER → synthesise proteins that are
transported OUT of the cell
● or lie freely in the cytoplasm → make proteins used WITHIN the cytoplasm
Smooth ER (3)
● No ribosomes attached to its membrane
● More tubular than rER, connected to rER
● Function: Synthesise substances like fats and steroids (e.g. sex hormones),
detoxifies harmful substances
Golgi body (2)
● Disc-shaped stacks of flattened spaces surrounded by membranes (visual: “WiFi
signal”) → Chemically modifies substances made by the SER and RER
● Vesicles (tiny ‘spheres’) fuse with one side of the Golgi body and pinch off from
the other → Golgi body stores and packages modified substances in vesicles for
secretion out of the cell
Mitochondria (1)
● Small oval-shaped organelles that conduct aerobic respiration → releases energy
to perform cell activities (e.g. growth and reproduction) by oxidising food
Vacuole (3)
● Fluid-filled space enclosed by a membrane.
● Many small vacuoles in animal cells → contain water and food substances
● One or few large central vacuole in plant cells, enclosed by tonoplast (ppm) →
contains cell sap that contains dissolved substances (e.g. sugars, mineral salts,
amino acids)
Cell wall (ONLY PRESENT IN PLANT CELLS) [3]
● Made of cellulose.
● Surrounds the cell membrane → Protects cell from physical damage, gives plant a
fixed shape
● Is fully permeable → Allows substances of all sizes to pass through into and out of
the cell
Chloroplast (ONLY PRESENT IN PLANT CELLS) [1]
● Oval-shaped structure that contains green pigment called chlorophyll → essential
for photosynthesis (makes food for the plant)
Centrioles (ONLY PRESENT IN ANIMAL CELLS) [2]
● A pair is present in an animal cell.
● Small, hollow cylinders usually found near the nucleus → Produce spindle fibres
that attach to centromere of chromosomes during nuclear division
Red blood cell [4]
● Contains haemoglobin → binds to oxygen and transports it around the body
● Has a circular, biconcave shape → (1) Increases surface area to volume ratio in
order to (2) increase the rate of gaseous exchange, (3) providing oxygen for cellular
respiration to release energy
● Does not have nucleus → Have more space to contain more haemoglobin that can
bind to more oxygen (NOTE: not to increase S.A. to Volume ratio)
NOTE: Sickle cell anaemia can be caused by abnormal haemoglobin production. Lowers
surface area to volume ratio → afflicted humans can have shortness of breath
Xylem vessels [3]
● Long hollow tubes extending from the roots to the leaves
● Is narrow and has no cross walls due to lack of protoplasm → reduce
obstruction of water flow through the lumen (a hollow space in the vessel)
● Walls are thickened with lignin → provides mechanical support to prevent
collapse of the vessel
RHC [1]
● Has a long and narrow protrusion → increases surface area to volume ratio of the
cell to increase rate of absorption of water and mineral salts
