Cell Structure and Organization Quiz 4

3 is a root hair cell, it absorbs water from the soil. 4 what is the xylem vessel which conducts water from the roots to the stems and leaves.1 is a red blood cell; 2 is a muscle

Structures of 1 are chloroplast which synthesises carbohydrates during photosynthesis; structure 2 is the cell membrane and structure 3 is the cell wall. The cell membrane is selectively permeable which allows the cell to control the entry of substance by allowing only some substances to path through but not others.

Mature human red blood cell has no nucleus, enabling it to carry more hemoglobin. It has a circular biconcave shape which results in the large surface area of the cell membrane. It is elastic and not rigid so it can squeeze through capillaries easily.

The red blood cell is a biconcave disc shaped cell with no nucleus. Xylem vessel is a dead, hollow tube with lignified cellulous cell wall. All other cells have a nucleus that controls all the chemical reactions and reproduction of the cell.

Structure A is composed of long hollow tubes formed by xylem cell members joined end to end, without any cross walls. They have no protoplasm and their cellulose walls are strengthened by lignin deposits.

The photomicrograph shows red blood cells with absorb oxygen and transport oxygen as  oxyhemoglobin.

The DNA in the nucleus (1) contains genes which code for polypeptides. The DNA is transcribed into mRNA which are then transported to the ribosomes (2) to be translated into proteins. The cell membrane (3) controls movement of substances in and out of the cell and is not involved in the synthesis and building of proteins.

The spiral structure is made up of lignified cellulous which provides mechanical support to the xylem vessels upright.

W is mitochondrion

Function: carries out aerobic respiration. (aerobic respiration occurs in the mitochondria where food substances are oxidized to release energy)

X is smooth endoplasmic reticulum

function: synthesis of fats and steroids.

Y is ribosome

function: formation of polypeptides (ribosome is the site for protein synthesis).

Z is rough endoplasmic reticulum

function: Transport of proteins made by ribosomes to the Golgi apparatus for secretion out of the cell.

A – (Golgi apparatus)- packing and processing of proteins.
B – (ribosome on rough endoplasmic reticulum) synthesis of protein.
C – (mitochondria) release of energy via aerobic respiration.
D – (smooth endoplasmic reticulum) synthesise substances such as fat and steroids.